MON-109: KeyComposer registers events without needing to add an event listener to it.

- Include the KeyComposer tests in the main test suite. Make them pass. (All were previously failing.)
- Deprecate KeyComposer#addEventListener and ensure events are triggered without calling it.
- Special-case EventManager to look up the event identifier correctly for KeyComposer events, because the identifier should come from the composer, not the target component.
Deprecate and empty out addEventListener
Add deprecation warning for KeyComposer#addEventListener.

- Montage.callDeprecatedFunction correctly handles null callbacks.
Merge pull request #1314 from asolove/MON-109

MON-109: KeyComposer registers events without needing to add an event listener to it.