allow for release and debug specific compile flags using cmake generator expression
Merge branch 'master' into renew-project-structure
Move directory traversal back to public API
Fix include directories in example plugins
Find GLFW in source builds on Linux
Fix compilation for gcc 4.9.1 on Linux
Compromise for GCC 4.8.2
Remove quotation marks as they confuse cmake
Merge branch 'master' into feature/screenshot_widget