Revert "convert to sprites"

This reverts commit 30bec59721a41acb422656161c9539eac8ad5fe9.
Revert "Background colors removed; LevelLayerDelegate for when Resume is tapped; Many NSLogs commented out; more de-referencing of UIKit stuff; first attempt at sprite sheet"

This reverts commit c200793ec9cf95d56e8dcf6d5f96f0fe08a613b9.
1st complete switch to sprite sheet.