Rearrange CBX.Xna library classes into proper namespace paths


The initial implentation was to have a generic game library "CBX.Xna" for Xna. But I never stopped to consider that the code that I am now working with and the code I will be working with in the future will also include silverlight and WP7. As such the namespace and general organization within the CBX.Xna library contains generic game related code yes but it need to be re-organized so that code that is specific to xna, silverlight or WP7 if organized properly. This will make the learning curve for third party developers much less difficult when starting to use the library.