closed #4557: Adds `EventListener::setEnabled/isEnabled`.
closed #4557: Comment fixes in CCEventListener.h.
issue #4557: Adds const for `EventListener::isEnabeld`.
issue #4557: Updates comments for EventListener::setEnabled/setPaused.
Also does whitespace cleanup and untabify codes. Thanks emacs. :)
issue #4557: Updates comments for EventListener::setPaused.
Merge pull request #6130 from dumganhar/iss4557-set-enabled-listener

closed #4557: Adds `EventListener::setEnabled/isEnabled`.