added function rotatePoints() that is applying a 3x3 rotation matrix to the points given within the vector pnts
refactored rotatePointToXY()
added function rotatePointsToXZ()

added functionality to find all nodes that are connected via edges and via element to other nodes; replaces all cout's with appropriate logog messages

fixed gmshinterface; fixed mesh copy constructor; fixed layer mapping; removed various TODO6 tags. DIRECT STs still not working; FEFLOW and TETGEN still not working; getsurface still not working

- added (a not yet finished version) CollapseMeshNodes programme
- changes in SimpleTests/MeshTests/CMakeLists.txt

[MeshCoarsener]
- new class used by CollapseMeshNodes
- can be used to make mesh nodes unique within a small epsilon radius

[MeshIO]
- added writing functionality for old mesh format

[GeoLib::Grid]
- changed interface (method getPointsWithinCube() -> getVecsOfGridCellsIntersectingCube())
- corrected documentation

[all mesh elements]
- added method clone()
- added method getType()
- removed attribute type from abstract base class Element

- added method to calculate a balanced workload

[new file SimpleTests/MatrixTests/MatVecMultPthreads.cpp]
- test matrix vector multiplication employing pthreads and balanced work

[files MathLib/LinAlg/Sparse/amuxCRS.{cpp,h}]
- implemented matrix vector multiplication employing pthreads that better balances the work

This reverts commit 05677165.

Conflicts:
	FileIO/XmlIO/XmlGspInterface.cpp
	README.md

- changed function scpr - for vectors of size 3 there is a specialisation of the function template which avoids OpenMP technique for very small vectors

- added class template LinearIntervalInterpolation

renamed namespace GEOLIB to GeoLib in order to be consistent with other OGS-libraries and directory names

- renamed method to access coordinates from getData() to getCoords()

- FileFinder.h
- FileTools.h
- TimeMeasurementBase.h
- quicksort.h

changes due to namespace changes in:
- PointVec.cpp
- Polygon.cpp
- AdjMat.cpp
- CRSMatrixReordered.cpp

in order to make the name of libraries, namespaces and directories more consistent the Base directory is know named BaseLib

added test application for mesh reading, fixed some bugs, reading and creating a mesh is working now; Mesh is (for now) a friend of Node, this should be fixed soon.

changed size_t to unsigned; included a few (yet unimplemented) methods for mesh-consistency checking