added check if nodes belong to any elements; reworked legacy mesh input to use getline command so that linux coding will hopefully be no longer a problem

fixed bug in MshEditDialog and added proper error management; removed openmp-loop in mesh class because of race condition

added rapidxml method for reading vtu files; fixed problem in Mesh::setNeighborInformationForElements - EDGE elements don't have neighbors anymore because they also dont have faces

Conflicts:
	FileIO/MeshIO/GMSHInterface.cpp
	FileIO/MeshIO/GMSHInterface.h
	MeshLib/Elements/Edge.h
	MeshLib/Elements/Element.cpp
	MeshLib/Elements/Element.h
	MeshLib/Elements/Hex.cpp
	MeshLib/Elements/Prism.cpp
	MeshLib/Elements/Pyramid.cpp
	MeshLib/Elements/Quad.cpp
	MeshLib/Elements/Quad.h
	MeshLib/Elements/Tet.cpp
	MeshLib/Elements/Tri.cpp
	MeshLib/Elements/Tri.h
	MeshLib/Node.h

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 documentation

* 'master' of github.com:ufz/ogs: (24 commits)
  added two options - one for output file name of the new mesh - another for the maximal collapse distance
  reset the mesh node ids correctly put information output within debug preprocessor instructions modified name of returned mesh
  write material number (the value) to the file
  inserted protected method setID() to class Node made class MeshCoarsener a friend of class Node
  delete the not used elem pointer variable
  made return value of virtual method Element::getEdgeNode() const this leads to the other changes of this commit in the inheritance hierarchy introduced a const_cast in Element::addNeighbor()
  added some documentation
  add _value of origin element to the new element created with reviseElement()
  made the behaviour of Edge::reviseElement() the same as other classes
  made ascci art consistent with other element documentation
  implemented Tri::reviseElement()
  fixed a bug creating Tri elements
  changed edge numbering in Quad::_edge_nodes implemented Quad::reviseElement() added more documentation to Quad::reviseElement()
  implemented reviseElement for class Tet documentation: - added edge numbering to prism sketch - added some docu to getEdgeNode()
  implemented reviseElement for class Pyramid documentation: added edge numbering to pyramid sketch
  implemented reviseElement for class Prism documentation: added edge numbering to prism sketch
  implemented Hex::ReviseElement() added more documentation to Hex::ReviseElement()
  documentation: added edge numbering to the sketch
  fixed a bug within documentation in doxygen (/latex) format
  using new method Element::reviseElement()
  ...

Conflicts:
	FileIO/Legacy/MeshIO.cpp

* master:
  removed additional but unnecessary const keywords
  Private t = y[i].
  Private i.
  Private j.
  Correct constness.
  Avoid unused argument warning.
  changed argument type from unsigned to bool
  introduced compiling options for Intel Compiler

Conflicts:
	scripts/cmake/CompilerSetup.cmake

- one for output file name of the new mesh
- another for the maximal collapse distance

put information output within debug preprocessor instructions
modified name of returned mesh