Added the Pause menu's update and present method

I coded the update and present method for pause mode. There are
currently three options: Reset Ball('s position), Resume(game), and
Quit(game)
Added white overlay of Menu Items

I added a white overlay of the play and settings button in it's own
stack just in case
Fixed moveToCenter method

Fixed the moveToCenter method so it will actually stay still instead of
continuously moving up and down.
Added renderPaused method

I added a method to render the pause menu. I also added some floats and
booleans used in the pause menu.