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
Constructors are protected
More tests converted
More tests working

[x]: Texture2D test working OK
Merge branch 'develop' into constructors_are_protected
fixes Sprite::setTexture()

Sprite::setTexture(std::string&)  works as expected.
It sets the texture rect of the sprite
Adds love to ShaderTest2 test

Improves the code in ShaderTest2
ParticleSystem  uses protected constructors
more protected constructors

Adds protected constructors for:

* ClippingNode
* ParallaxNode
* RenderTexture
* TMXTiledMap
CCControlButton has protected constructor
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
Fixed crash