Untangle the mess

Barrage was beginning to feel like a bit of a mess.  Some of the code I had put together just felt very tacked on and unkept.  I decided I would like to re-write some of it so I took this opportunity to move the project from XNA 3.1 to 4.0 incase I don't get it done by the beginning of January, which will be to cut off for XNA 3.1 submissions.  I really like some of the changes I made and it feels like a good move.  Although I probably should get cracking on an update to Ripple before 3.1 goes away for good.