Changed AppleClang no warning flag from no-reorder-ctor to no-reorder. Disable unroll-all-loops for GNU when IWYU is enabled. Fixed Cycle in include-mapping.

Changed typedefs to using.

Add msvc warning level W4 and removed most of the warnings. Some of the warnings are suppressed (see MSVC.cmake)

Update cmake to dev version.

Move VirtualFluids header to src.
Add CI file and add files, only existing in the open source version.

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).

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