all ARC readiness issues fixed (as far as compilation is concerned)
ARC readiness: leave ThoMo as MRC, remove SCEvent bridge casts
ARC readiness: keep some other libs MRC for now
ARC conversion succeeded (SB unusable in current state)
fixed scene nodes not retained
added WARN macro, warn use of cocosscene singleton when nil
fixed several (unrelated) analyzer warnings
some xib change (plugin version, from xcode)
fixed the blank cocos2d view
converted TabBar, Inspector and other "lib" classes to ARC
Merge branch 'refs/heads/develop' into convert-to-ARC

Conflicts:
	SpriteBuilder/SpriteBuilder.xcodeproj/project.pbxproj
	SpriteBuilder/ccBuilder/UsageManager.m
	SpriteBuilder/ccBuilder/en.lproj/MainMenu.xib
added SK reader test project