Get rid of extraneous classes in GameManager
Make WebSocket[A] a model-wide class.

- Move `import GameManager._` inside the implementation.
Refactor out GameType

I put it in a utils package since it's used in the controller, model,
and view.
I might need to define the game types themselves in the controllers
package, since they depend on both the model and the view.
We should also follow the java package naming convention and put our
folders under `me.quickga._`, since now we have to import in the Build
file under `_root_`, which is unweildy.
I want to also do some refactoring and take out the view's dependencies
on the game type.
More GameType refactoring!

- GameType is now just a trait in the utils folder.
- Brought back the `binders` package. Put every type of binder in here
  (if we make more types)
- Put the specific game types (ConnectFour, TicTacToe, etc.) in
  controllers.Games, since they depend on both the model and view.
  `GameType` is an abstract type that contains all information on a
  game.
- Refactoring on the game.scala.html page: now takes in the id and
  username and a game type and automacially loads the websocket URL.
Merge branch 'gametype'