CCControlButton: Fixed internal state when the button is selected
CCScrollViewLoader: do not try to set ScrollView's Container if container read from CCBI file is null
CCScrollView: fixed behavior of CCScrollView::setContainer (properly works with passed NULL container)
CCControlButton: Allows on-the-fly background image change
CCLabelTTF: added some asserts for checking m_tDimensions validity
CCControlUtils: fixed CCControlUtils::CCRectUnion that gives incorrect origin result
CCControlButton: fixed refactoring of needsLayout method using computeContentSize() and layoutTitleLabel()
CCDirectorCaller.mm: fixed black screen at startup by drawing on screen immediately
CCNodeLoaderLibrary: registered CCControlSlider to be able to be loaded from CCBReader
CCTouchDispatcher: virtualized methods createTargetedTouchDispatcher and forceRemoveDelegate() to allow overriding by CCSceneGraphTouchDispatcher
CCLayer: now allows NOT to override ccTouchBegan. Simply returns false if no script installed or not handling touch down event.
CCControl.cpp: fixed removal of target when this target was added several times
CCTouchDispatcher: removed CCAssert in forceAddHandler to allow multiple calls with same delegate without crashing in debug
CCDirector.cpp: properly calling CCScene::onExitWillStart when transitioning to new scene
Merge branch '2.1.5-DOW' of https://github.com/daysofwonder/cocos2d-x into 2.1.5-DOW