Add scale ratio to button touchdown
Merge branch 'develop' into fix-button-scale-to
Merge commit 'refs/pull/4085/head' of git://github.com/cocos2d/cocos2d-x into iss3619

Conflicts:
	extensions/GUI/CCControlExtension/CCControlButton.cpp
Merge pull request #4997 from dumganhar/iss3619

Merge PR #4085: Fix of ControlButton doesn't support to set scale ratio of touchdown state