Fixed bug where player/background wasn't in view.

* Translated(?) between the virtual GAME_WIDTH/HEIGHT and the actual viewport size in the setNewCameraPos. This fixed the player not being fully on the screen.
* Changed the backgroundView render to use the provided viewport instead of fixed width/height.
* Made sure the frustum is also updated when the camera is updated.
Merge pull request #45 from Jokab/cameraViewportFix

Fixed bug where player/background wasn't in view.