title: Viewport presists on changing screens
body: <p>My game I made is currently confusing, but it is long so I don't have the nerve to change it. So My PlayState is made without a camera and is made on the calculations of % od the WIDTH...</p>
  
  <p>But now I made my MainMenu with the camera's and viewport's, because well, it was alot faster... </p>
  
  <p>Now if I start the PlayState directly, it works normal. But if I start the PlayState from the MainMenu, the viewport seems to presist, and my game is totally weird. The 0,0 seems to be at middle, at none of the logic works...</p>
  
  <p>So how do I reset the viewport? Or if I am correct, the setProjectionMatrix(camera.combined) seems to be still there. How to remove that?</p>