Removing LevelGrid creation from Game class
This was just creating a default LevelGrid anyway, which is handled by the TestLevel constructor if it isn't passed in.
Reset LevelGrid at level start and end
Reset shifting flags to false on level end
Merge pull request #13 from brwyatt/fix-return-to-level-after-menu

Fix return to level after menu
Merge pull request #14 from brwyatt/master

Merge from Master