Added countdown finished callback accessible from angular callback. Triggers when countdown finishes on it's own (not when it is stopped by a user). Useful if your app should take somea action when the countdown is reached.
re-added copyright I accidentially removed.
Merge branch 'master' of https://github.com/itslenny/angular-timer into itslenny-master

Conflicts:
	app/js/timer.js
	dist/angular-timer.js
	dist/angular-timer.min.js
	index.html
Merge branch 'itslenny-master'