Also implemented decal atlas, so projectors and other stuff can be added. Sidenote: Had to make RID hashable, so some unrelated includes changed in order to include it in hashfuncs.h
VisualServer -> RenderingServer PhysicsServer -> PhysicsServer3D Physics2DServer -> PhysicsServer2D NavigationServer -> NavigationServer3D Navigation2DServer -> NavigationServer2D Also renamed corresponding files.