Fix listenToOnce for stopListening

`obj` push to @listeningToOnce, because may conflict with `obj` by
@listenTo. Delete `obj` from @listeningToOnce if callbacked.
And fix stopListening bugs.
Merge pull request #448 from yaakaito/fix/stop-listening-for-once

[resubmit] When listenToOnce, Event can stopToListening