Merge pull request #9 from GavinDBrown/master

Fixed bounding box for sprite2
changed asteroid image
Merge pull request #10 from sumnerjj/master

changed asteroid image
Added desplay for live Velocity and Friction information. Further updated friction calculation. Changed the representation of Velocity and Friction to be of type float. However, clicking about 10 to 20 degrees off an axis still produces a small artifact in movement.