Added const to CCNode's getTag & getContentSize
Merge remote-tracking branch 'upstream/master'
Added const to CCNode::getChildrenCount()
Merge branch 'master' of https://github.com/metalgit92/cocos2d-x into metalgit92-master
fixed #2149: "const CCSize& CCScrollView::getContentSize()" --> "const CCSize& CCScrollView::getContentSize() const".
Merge pull request #2554 from dumganhar/iss2149-const

fixed #2149: Adding const qualification to some CCNode's getters