On level view controller, removed title and vertically centered board.
Merge pull request #33 from zsweedyk/feature-board-center

On level view controller, removed title and vertically centered board.
Added basic "return to level select" and "restart level" functionality.
Added alert views as confirmation dialog.
Added background images and started styling text.
Improved menu aesthetics, including adding a wide rectangular frame and computer mascot.
Improved spam mini game aesthetics.
Deleted password mini game view controller, since we haven't been using it.
Moved the mini game's call to completeMiniGameWithSuccess to a completion block so it runs after the view controller is dismissed.
Added proper image buttons.
Merge branch 'feature-level-buttons' into feature-basic-aesthetics
Made the two buttons on the level view controller properly styled image buttons.
Fixed minor style issues.
Finished disabling user touch of start/end button
Merge pull request #35 from zsweedyk/feature-level-buttons

Added "return to level select" and "restart level" buttons to the level view controller.
Merge pull request #36 from zsweedyk/feature-basic-aesthetics

Improved aesthetics, including spam mini game
Also disabled touch for invisible cells
Merge pull request #40 from zsweedyk/feature-disableStartEndButton

Finished disabling user touch of start/end button
Merge branch 'develop' into feature-endOfLevel
Merged changes from develop, got rid of password view controller.