Update PlayProject to play.Project for Play 2.1 support

I think with Play 2.1 you're supposed to use play.Project instead of PlayProject. I updated it in my branch, compiled it, and am using it in my application with play.Project and it appears to be working. Everything else in your branch looked fine as far as I can tell and is working for me (again, as far as I can tell).

[Disclaimer: Still new to Play and Scala myself, so I could be totally wrong]