Emitter

on( event, listener )

Create an event listener

Name	Type	Description
`event`	string	The name of the event to listen for
`listener`	function	A callback to run when the event is fired.

removeListener( event, listener )

Remove an event listener

Name	Type	Description
`event`	string	The name of the event that we are removing a listener from
`listener`	function	The callback that we are removing

emit( event )

Emit an event

Name	Type	Description
`event`	string	The name of the event to emit

once( event, listener )

Create an event listener that will only fire one time.

Name	Type	Description
`event`	string	The name of the event to listen for
`listener`	function	A callback to run when the event is fired.

new Emitter()