Therefore the muparser cmakeLists.txt was used, but a modified:
 - name is corresponding to the original file: muparser (in lowercases)
 - removed the install
 - adds public include directory : CMAKE_CURRENT_SOURCE_DIR/include.  --> also adapt the include from the dependent fles.
 - adds link to OpemMP

CXX 11 is now required. (CMake throws an error if cpp11 is not available).

Exclude the cmake .in.h file from the cmake target.

Add public target include directories to the cmake targets. Therefore the IncludeList.cmake files are not necessary anymore.
ADapt the export macros in the gks libraries.
Add 3rd/vtk helper cmake macro.
Gorup muparser into 3rd subfolder in visual studio project.

Make the cmake project more flexible while removing the CMAKE_SOURCE_DIR usage.

Make the cmake project more flexible while removing the CMAKE_SOURCE_DIR usage.

Remove the old write/read functions.

Remove unused stuff and the global include from VirtualFluidsDefinition.h. Adds missing export includes.

Warning: [-Wbackslash-newline-escape]
https://stackoverflow.com/questions/31673945/clang-backslash-and-newline-separated-by-space-in-single-line-comment

Moved numers/geomtry3d to /geometry3d.