Added the ability to remove registered inputs.
- Changed legato.closet to an object.
- legato.in now returns the id of the newly registered input.
- Can remove an input with legato.removeInput.
- Renamed legato.remove to legato.removeRoute.
- Added an integration test to make sure that legato and legato.midi are functioning together.
- Added rtMidiMock so that the underlying midi layer is consistently mocked between tests.