added menu item to create sprite kit project
added "engine" setting to ProjectSettings to differentiate CC vs SK
updated ProjCreator to create different project based on "engine"

Conflicts:
	SpriteBuilder/libs/cocos2d-iphone
BuildDistribution.sh: added zip & copy of generated sprite kit template project
implemented node filtering based on project's "engine" type

Conflicts:
	Test/SpriteKitReader-Experimental/SpriteKitReader-Experimental/SKReaderTestData.spritebuilder/SKReaderTestData.ccbproj