Canvas Grid

- Added Grid Support for the ZSCanvasViewController
    - Added ZSGrid which represents a grid layout in a view which has support for sprite snapping.
    - Added ZSCanvasView and made it the main view for the ZSCanvasViewController.
    - Added ZSSettingsViewController to control the way the grid functions on the canvas.
    - Added a "Settings" option to the main menu on the canvas.
- Started to play around with getting the UIMenuController to work but haven't been able to yet.