- CHANGELOG.md reformatted to CHANGELOG.rst
- Added CONTRIBUTORS.rst
- The `listeners` method no longer returns the raw list of listeners, and
instead returns a list of unwrapped listeners; This means that mutating
listeners on the EventEmitter by mutating the list returned by
this method isn't possible anymore, and that for once handlers this method
returns the unwrapped handler rather than the wrapped handler
- `once` API now returns the unwrapped handler in both decorator and
non-decorator cases
- Possible to remove once handlers with unwrapped handlers
- Internally, listeners are now stored on a OrderedDict rather than a list
- Minor stylistic tweaks to make code more pythonic