Merge remote-tracking branch 'origin/develop' 

merge 

fixed OpenGLSystem crashing when querying invalid pixel coordinate 

merge develop 

merge 

Merge branch 'develop' of github.com:phiste/kengine 

optimized includes in SfSystem 

made LuaCollisionSystem only use handlers instead of global table 

added support for cameras to SfSystem + renamed MetaComponent to Grap… …hicsComponent

Merge branch 'master' of github.com:phiste/kengine into develop