Made publish validation happen always

On the theory that this validation is meant for development as an ongoing check for runtime errors, I made validation happen even if no one is listening to the given channel. This way you don't have to set up a listener to test that the event you're emitting is valid.
Merge branch 'patch-3' of https://github.com/sderickson/Validated-Backbone-Mediator into sderickson-patch-3

Conflicts:
	backbone-mediator.js
Merge branch 'patch-3' of https://github.com/sderickson/Validated-Backbone-Mediator into sderickson-patch-3

Conflicts:
	backbone-mediator.js
Merge branch 'sderickson-patch-3'