Created a ranged enemy that throws spears

-Created a Spear sprite
-Created SpearEnemy.cs
-Created Spear.cs
-Revised code in Projectile.cs and LevelObject.cs, as well as added properties

-A majority of the code in Projectile.cs and Enemy.cs needs to be heavily refactored to allow for maximum flexibility
Made it so enemies can have a resistance to certain weapons
Finished Creating the Basic Shop System

-Finished the design of the Shop system
-Made the Shop accessible, and made Shop Items display on the Shop
-Added an ImagePath property to ShopItem.cs so that the items can be displayed in XAML
-Made it so ShopItems are used when clicked on
-Fixed the blurriness issue by not setting the PreferredBackBufferWidth and PreferredBackBufferHeight at all
Merge remote-tracking branch 'origin/ContinueShopDesign' into EnemyWeaponWeakness
Merge branch 'EnemyWeaponWeakness'