[web] Added some developer docs test content.

web/content/docs/benchmarks/elliptic/groundwater-flow-neumann.md

++++
+date = "2017-01-31T14:27:10+01:00"
+title = "Groundwater flow (Neumann)"
+
++++
+
+## Equations
+
+{{< vis url="square_1e4_pcs_0_ts_1_t_1.000000.vtu" >}}
+
+We start with simple linear homogeneous elliptic problem:
+$$
+\begin{equation}
+k\; \Delta h = 0 \quad \text{in }\Omega
+\end{equation}$$
+w.r.t boundary conditions
+$$
+\eqalign{
+h(x) = g_D(x) &\quad \text{on }\Gamma_D,\cr
+k{\partial h(x) \over \partial n} = g_N(x) &\quad \text{on }\Gamma_N,
+}$$
+where $h$ could be hydraulic head, the subscripts $D$ and $N$ denote the Dirichlet- and Neumann-type boundary conditions, $n$ is the normal vector pointing outside of $\Omega$, and $\Gamma = \Gamma_D \cup \Gamma_N$ and $\Gamma_D \cap \Gamma_N = \emptyset$.
+
+## Problem specification and analytical solution
+
+{{< vis url="cow.vtp" height="300" >}}
+
+We solve the Laplace equation on a square domain $[0\times 1]^2$ with $k = 1$ w.r.t. the specific boundary conditions:
+
+$$
+\eqalign{
+h(x,y) = 1 &\quad \text{on } (x=0,y) \subset \Gamma_D,\cr
+h(x,y) = 1 &\quad \text{on } (x,y=0) \subset \Gamma_D,\cr
+k {\partial h(x,y) \over \partial n} = 1 &\quad \text{on } (x=1,y) \subset \Gamma_N,\cr
+k {\partial h(x,y) \over \partial n} = 0 &\quad \text{on } (x,y=1) \subset \Gamma_N.
+}$$
+
+The solution of this problem is
+$$
+\begin{equation}
+h(x,y) = 1 + \sum_{k=1}^\infty A_k \sin\bigg(C_k y\bigg) \sinh\bigg(C_k x\bigg),
+\end{equation}
+$$
+where $C_k = \frac{2k-1}{2} \pi$ and $A_k = 2 \Big/ \Big(C_k^2 \cosh\big(C_k\big)\Big)$.
+
+## Input files
+
+The main project file is [square_1e2_neumann.prj](https://github.com/ufz/ogs-data/blob/master/Elliptic/square_1x1_GroundWaterFlow/square_1e2.prj). It describes the processes to be solved and the related process variables together with their initial and boundary conditions. It also references the mesh and geometrical objects defined on the mesh.
+
+As of now a small portion of possible inputs is implemented; one can change:
+ - the mesh file
+ - the geometry file
+ - introduce more/different Dirichlet boundary conditions (different geometry or other constant values)
+ - introduce more/different Neumann boundary conditions (different geometry or other constant values)
+
+The geometries used to specify the boundary conditions are given in the [square_1x1.gml](https://github.com/ufz/ogs-data/blob/master/Elliptic/square_1x1_GroundWaterFlow/square_1x1.gml) file.
+
+The input mesh `square_1x1_quad_1e2.vtu` is stored in the VTK file format and can be directly visualized in Paraview for example.
+
+## Running simulation
+
+To start the simulation (after successful compilation) run:
+```bash
+$ ogs square_1e2_neumann.prj
+```
+
+It will produce some output and write the computed result into the `square_1e2_neumann.vtu` for visualization with Paraview.
+
+The output on the console will be similar to the following one (ignore the spurious error messages "Could not find POINT..."):
+```
+info: This is OpenGeoSys-6 version 6.0.7-619-ge761162.
+info: OGS started on 2016-12-05 11:16:47+0100.
+info: ConstantParameter: K
+info: ConstantParameter: p0
+info: ConstantParameter: p_neumann
+info: ConstantParameter: p_Dirichlet
+info: Lis options: "-initx_zeros 0 -i cg -p jacobi -tol 1e-16 -maxiter 10000"
+info: Initialize processes.
+info: Calculated search length for mesh "square_1x1_quad_1e2" is 1.000000e-09.
+info: Solve processes.
+info: [time] Output took 0.00378108 s.
+info: === timestep #1 (t=1s, dt=1s) ==============================
+info: [time] Assembly took 0.000336885 s.
+info: [time] Applying Dirichlet BCs took 3.60012e-05 s.
+info: ------------------------------------------------------------------
+info: *** LIS solver computation
+info: -> precon: 1
+info: -> solver: 1
+info: -> solve
+info: -> status: 0
+info: -> iteration: 35
+info: -> residual: 6.16949e-17
+info: -> time total           (s): 0.000153065
+info: -> time iterations      (s): 0.000147343
+info: -> time preconditioning (s): 5.72205e-06
+info: -> time precond. create (s): 0
+info: -> time precond. iter   (s): 5.72205e-06
+info: ------------------------------------------------------------------
+info: [time] Linear solver took 0.000437021 s.
+info: [time] Iteration #1 took 0.000844002 s.
+info: [time] Solving process #0 took 0.0011301 s in timestep #1.
+info: [time] Output took 0.00462508 s.
+info: [time] Timestep #1 took 0.00580406 s.
+info: OGS terminated on 2016-12-05 11:16:47+010
+info: [time] Execution took 0.016582 s.
+```
+
+A last major part of the output was produced by the linear equation solver (LIS in this case) showing good convergence.
+
+## Results and evaluation
+
+The result, written in the `square_1e2_neumann.vtu`, can be visualized with Paraview, for example.
+
+Loading the `.vtu` file in Paraview will show following image:
+{asset:373:img}
+
+Compared to the analytical solution presented above the results are very good but in a single point:
+{asset:374:img}
+
+Both Dirichlet boundary conditions are satisfied.
+The values of gradients in x direction along the right side and y directions along the top sides of the domain a shown below:
+{asset:375:img}
+The homogeneous Neumann boundary condition on the top side is satisfied (ScalarGradient_Y is close to zero).
+The inhomogeneous Neumann boundary condition on the bottom is satisfied only for $y > 0.3$ (where the ScalarGradient_X is close to one) because of incompatible boundary conditions imposed on the bottom right corner of the domain.

web/content/docs/devguide/getting-started/introduction.md

++++
+categories = ["category"]
+description = ""
+images = ["/2016/10/image.jpg"]
+date = "2017-01-14T22:51:41+01:00"
+title = "Welcome!"
+weight = 1
+draft = true
+tags = ["tag1","tag2"]
+# next = "prerequisites.md"
+
++++
+
+In this help section you will find everything related to development. Please walk through the Getting Started-section **step by step**. At the end you will have the latest OGS source code, the OGS finite element simulator compiled and everything you need to start developing for OGS! This first section of the developer guide will give you just a brief introduction, make sure to read the more advanced topics after you have familiarized yourself with the basics.
+
+{{< figure src="/docs/devguide/getting-started/test.jpg" class="img-responsive" >}}

web/content/docs/devguide/getting-started/prerequisites.md

++++
+tags = ["tag1","tag2"]
+categories = ["category"]
+description = ""
+images = ["/2016/10/image.jpg"]
+date = "2017-01-14T22:56:13+01:00"
+title = "Set Up Prerequisites"
+author = "Lars Bilke"
+weight = 2
+draft = true
+
+# back = "introduction.md"
+
++++
+
+## Minimum requirements
+
+The minimum prerequisites to build OGS are:
+
+- Git (version control tool, at least version 1.7.x)
+- CMake (build configuration tool, at least version 3.1)
+- A compiler with C++11-support
+- Conan package manager (TODO crossref) OR required libraries (TODO crossref)
+
+## Step: Install a compiler
+
+### Windows
+
+Because the C++11-standard is supported since **Visual C++ 2013** you will need at least **Windows 7** (64-bit recommended). It is perfectly fine to use the free Community Editions of Visual C++. We support the **2013 edition** and newer.
+
+Download Visual Studio and install it:
+
+- [Visual Studio Community 2015](https://go.microsoft.com/fwlink/?LinkId=532606&clcid=0x409)
+
+### Linux
+
+If you have a recent linux distribution you should also have a recent gcc. Please check that you have at least **gcc 4.9**:
+
+{{< highlight bash >}}
+$ gcc --version
+gcc (GCC) 4.6.1
+{{< /highlight >}}
+
+### Mac
+
+Please install Xcode from the App Store. Then please run the following command in the terminal to install the command line tools:
+
+{{< highlight bash >}}
+$ xcode-select --install
+{{< /highlight >}}
+
+Open Xcode one time to install some other Xcode stuff.
+
+Now also install the Homebrew package manager:
+
+{{< highlight bash >}}
+$ ruby -e "$(curl -fsSL https://raw.github.com/mxcl/homebrew/go/install)"
+$ brew doctor
+{{< /highlight >}}
+
+The Homebrew package manager is needed for installing other libraries and packages. It is just like a linux package manager.