[DF-478] SceneGraph refactoring - recovered changes lost during merge.
[DF-478] SceneGraph refactoring - recovered SceneGraphManager refactoring.
[DF-478] SceneGraph refactoring - recovered RebuildSceneGraph for separate node refactoring.
[DF-478] SceneGraph refactoring - recovered Win32 changes.
Merge remote-tracking branch 'origin/ParticleEditorQT_Refactoring_SceneGraph' into ParticleEditorQT_SpritesRepack

Conflicts:
	Tools/ResourceEditor/Classes/GameCore.cpp
	Tools/ResourceEditor/ResourceEditorQt.xcodeproj/project.pbxproj
	Tools/ResourceEditor/ResourceEditorQtVS2010.vcxproj.filters
Base infrastructure for sprite packer.
Add basic support of sprite repack
Helpers for SpriteRepacker
Update proj file for xcode
[DF-421] merged with pull request