Merge pull request #296 from gena-m/master

box2d and box2d Tests
Merge pull request #297 from gena-m/master

box2d optimization
added missing file
fix android tests build.
build error fix for the tests.
fixed box2d tests
Merge branch 'master' of https://github.com/Cocos2DXNA/cocos2d-xna
fixed copying manifolds
Merge branch 'master' of https://github.com/gena-m/cocos2d-xna