Navigation event system/mapping WIP
Merge branch 'master' into navigation
navigation (QtEventTransformer + QtViewerMapping + WorldInHandNavigation + CameraCapability)
close to functional, but limited and incomplete (example usage missing)
implement CameraCapability + refactor Camera
Merge branch 'master' into navigation
move QtEventTransformer to gloperate-qt (where it belongs!)
Merge branch 'master' into navigation
slight refactoring of navigation system
navigation is working!!! (a very simple keyboard navigation for CubeScape anyway)
add rotation with arrow keys
remove EventType (same function is now fulfilled by MouseEvent::Type
and KeyboardEvent::Type)
Merge branch 'master' into navigation

Some weird problems with plugin system (finding of plugins)

Conflicts:
	source/examples/ViewerQt/main.cpp
	source/examples/basic-painters/include/basic-painters/cubescape/CubeScape.h
	source/examples/viewer-qt/CMakeLists.txt
Merge branch 'master' into navigation

Conflicts:
	source/examples/viewer-qt/main.cpp
implement AbstractEventProvider (+ System around it) + refactoring
Use glm::pi instead of M_PI
add glm constants include to use glm::pi
implement QtMouseEventProvider
Rename AbstractNavigation to AbstractInteraction
Reimplement enforceRotationConstraints
implement QtMouseEventProvider