[cocos2d] target cocos2d 2.1. Fix extract dir
[Chipmunk] bump to 6.1.5. Fix for new version
Merge branch 'fixcocos2d' of github.com:StephaneDelcroix/monotouch-bindings into StephaneDelcroix-fixcocos2d

Conflicts:
	chipmunk/binding/Makefile
[Cocos2D] Some fixes to ApiDefinition, AssemblyInfo and samples to match the new update
Merge branch 'StephaneDelcroix-fixcocos2d'