Backgrounds as purchasable items are added
noBackgroundLabel is hidden when image is available.
A bit of refactoring.
Merge branch 'backgrounds'
Merge branch 'master' of https://github.com/emilyems/CS408--Critter-Friends

Conflicts:
	Tiny Tastes.xcodeproj/project.pbxproj
	Tiny Tastes/Shop/ShopInteriorViewController.m