Update _bPlaying on CCActionObject.

The method CCActionObject::isPlaying() return the state of the member var _bPlaying,
which is initially declared false and never updated. The change updates this variable
across the play, pause, stop and end states of the action.
Merge pull request #8643 from huangshiwu/v3_fixDrawNodebug

fix DrawNode's memory leak -- delete vaos those are generated and forget...
Fixing merging, identation only conflicts.
Fixing conflict, use of macro function.
Merge pull request #7062 from maldewar/v3

Update _bPlaying on CCActionObject.