issue #2771: implement contact callbacks
issue #2771: fix some retain/release bugs
issue #2771: edit physics effect with all bodies and fix some bugs
issue #2771: add physics pump demo and fix bugs
issue #2771: edit listener
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-x into iss2771_physical
issue #2771: fix vs compile errors
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-x into iss2771_physical
issue #2771: enhance Listener use EventListener mechanism
issue #2771: fix some code style
issue #2771: fix some code style
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-x into iss2771_physical
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-x into iss2771_physical
Merge branch 'fix_event_listener'
pXmlBuffer is not null terminated
Update android-build.py

Fixing wrong capital letter, `samples/JavaScript` --> `samples/Javascript`
Update run-script.sh

Adding soft-link for `samples/Cpp/SimpleGame/proj.android/obj`.
Merge pull request #4073 from ledyba/fix_ccuserdefault

closed #3107: When parsing XML using TinyXML, the data size has to be specified. Otherwise, XMLDocument::Parse(data) will treat data as a null-terminal string. It may cause potential issues.
Update CHANGELOG [ci skip]
Update AUTHORS [ci skip]