Finished the Design of the Pause Menu

-Redesigned the Pause Menu to have a Resume button, music and sound volume controls, and a Quit button
-Coded the Resume and Quit buttons. Quitting works but may be missing a few things. Need to verify this.
-Created the QuitLevel() method in Level.cs
-Displayed the next level number in the Shop to the left of the "Done" button
Merge remote-tracking branch 'origin/FinishPauseMenu' into ArcherShopIcons