Added the last piece of music, the Level music, to the game

-Fixed a small error with the CastleIconBigger sprite
-Loaded and made the level music play when starting a new game or moving onto the next level
-Fixed the weapon keyboard shortcuts to switch to the correct weapons
Replaced the current level song with a newer one
Finished Redesigning the Shop

- Finished redesigning the Shop to scale to different screen sizes and resolutions
- Made the Fort and Helpers sections of the Shop have a 2x2 matrix of items. This was done by having four separate GridView controls on each section
- Changed the template for each ShopItem. The level of the ShopItem is now displayed under the icon, and the description is displayed under everything else
- ShopItems with an infinite number of purchases will not have their level displayed
- Renamed the FortifyCastle item to StrengthenWalls everywhere in the project
- To keep the HUD consistent in the How To Play tutorial, switched the BorderBrush of the RedBoxBorder between Transparent and Red instead of switching the BorderThickness between 0 and 3
Merge remote-tracking branch 'origin/FinishShopDesign' into NewLevelMusic
Added wav file for Funk Game Loop
Merge branch 'NewLevelMusic'