Add project_warnings and project_options target. A lot of clean up in cmake....
- modernize cmake project by adding project_warnings and project_options interfacetarget
- A lot of clean up in cmake
- Disable compiler warnings specific for each library
- Remove Export-Header
- Unify VirtualFluids CMake Options
- Small Refactorings in code to satisfy new compiler warnings
Closes #145 (closed)
Edited by Sören Peters