Jmex.awt package

Under direction from Mark I've moved the Canvas classes into the jmex.awt package I originally created for the AWT input classes.  Potentially we could (eventually) move all AWT code into this package to allow folks to decide against having AWT dependencies.  Holler if you feel like something was moved that shouldn't have been or something else should be moved.

I also went ahead and added generation of jme-awt.jar to the build script.