Use tags with TImers

This small library extends the timer object (performWithDelay, pause, resume, and cancel) to use optional tags.
It uses a tag of "default" for all timers created without the tag. This way, if you are cleaning up a scene or handling events like a phone call, you can do timer.cancel("default") to cancel all tags. If you DO use tags, you will need to cancel those by calling them.

Works with Corona build #: