Merge pull request #4 from AngeredBovine/master

First Commit - Framework changes - Game Object, Matrix2X, Asteroid, Cont...
Adding a main menu xaml file.
Merge pull request #5 from AngeredBovine/master

Bouncing Completed, Asteroid and Target Images
Adding the Main Menu and a shell for the upgrade menu as well as some art assets.
Merge branch 'master' of github.com:just-joel-and-justin/mobile-experiments
Changing the startup view.
Merge pull request #6 from JoelAlexander/master

Art assets and some art assets.
Added a class that manages a saved game on file on the phone.