Throttled rewrite + RemoveListener support

Removed timestamp(), removed strconv import, added createEvent(), added
throttle type, added addThrottle(), added tests for throttle's
interaction in RemoveListener() and SetMaxListeners(), and clarified
some docs.
Compare listeners using reflect instead of fmt

Added listener.Equals().

Also fixed a typo in Once()'s test.
Updated RemoveListener doc
Merge pull request #1 from Mischanix/master

Throttled rewrite + RemoveListener support