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.
Fixing merging, identation only conflicts.
Fixing conflict, use of macro function.
Merge pull request #7062 from maldewar/v3

Update _bPlaying on CCActionObject.