Added Reload functionality to Guns

-Guns now reload an amount of ammo based on their TotalAmmo, ClipSize, and ClipAmmo
-Manual reload has been added if the player presses the R button
  -If the gun has ammo left but no ammo in the clip and the player shoots, it will automatically reload
Added picking up guns and allowed switching guns

-The player can switch between the Primary and Secondary gun by pressing the E key
-Fixed a problem where invincible hurtboxes weren't set properly and hitboxes wouldn't check for them being invincible
Merge branch 'GunMechanics'