Merge pull request #8 from yonekawa/master

Fix 
=> world.new_body failed when block is not given.
Adds:
  => Animations Beta
  => Box2D Vendor Project updated with Circles
Merge branch 'master' of github.com:rubymotion/Joybox
Merge branch 'master' of git://github.com/yonekawa/Joybox into yonekawa-master

Conflicts:
	lib/joybox/box2d/body.rb