Added benchmarks
Improved caching so that wildcard emits are not slower anymore
Added filterOnce
Added 'filters'; Using default callback for filters if none is provided;
Improved error event emitting

- Invoking error filters
- Added 'cause' to scope with the original scope
Added filtersMatching, removeAllFilters and removeMatchingFilters

Renamed removeAllMatching to removeMatchingListeners.
Don't leak empty listener and filter entries
Cleanup
Don't emit 'error', 'new*' and 'remove*' events on matchers