issue #2771: add class PhysicsDebugDraw
issue #2771: rename PhysicsWorld::create() to PhysicsWorld::construct(), fix some bugs
issue #2771: add pointQuery
issue #2771: edit assert message
issue #2771: change pointQuery implements
issue #2771:  add comment and improve API
issue #2771:  add comments
issue #2771:  fix bugs
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-x into iss2771_physical
Merge branch 'iss2771_physical' of https://github.com/boyu0/cocos2d-x into iss2771_physical
fix path for windows
Fixed crash
fix some warnings
fix some hungarial
Merge pull request #4283 from minggo/fix-warning-hungaria

[ci skip]apply cocos2dx coding style
Merge pull request #4280 from lite3/develop

[ci skip]fix path for windows
issue #2771:  delete PhysicsSlidingJoint and PhysicsSpringJoint. add joint tests, fix bugs
issue #2771:  fix some api name and code style
fix bugs: delete initTest functions.
Merge branch 'develop' into develop_nutty_modify_bugfixed