issue #2771: physical

1. Add PhysicsWorld function set/getUpdateRate and set/getSpeed.
2. Change name PhysicsQueryRectCallbackFunc and PhysicsPointQueryCallbackFunc to PhysicsRectQueryCallbackFunc and PhysicsQueryPointCallbackFunc
3. Change name PhysicsShape::calculateDefaultArea to calculateArea, and set it to protect function.
4. add some get/set functions
5. add documents.