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
pbxproj: updated to "recommended settings" according to Xcode
fix tab bar icons (build settings: combine high res artwork must be NO)
some image files were assigned to both SpriteBuilder and cocos2d targets, removed them from cocos2d target
updated generated template project:
- removed txt files (changelog etc) files from copy bundle resources phase
- updated template project's warning build settings (specifically those helping beginners with hard-to-find mistakes, like shadowed local vars)