New rendergraph concept

Improved staticSceneObject handling using an experimental rendergraph
for more optimal rendering.
Updated glm version
New node rating class EqualityRating. Made Cost and Rating virtual.
Introduced IoCenter

The IoCenter is now set between the engine&controls and the
communication hub.
Also fixed a possible crash when the Rendergraph is empty.
Merge remote-tracking branch 'origin/invor' into ai
Added new files to Makefile.