XCode 5 refactor

Since this is an iOS 7 widget, you can assume developer use will be in XCode 5 or later. Did some general code cleanup and refactoring with that in mind.

Overview:
  - moved private ivars into internal interface
  - removed delegate setter that was performing behavior that is already the default
  - changed properties to *strong* rather than *retain* since compile with ARC
  - made class wide constants conform to Objective-C stytle
  - moved dangling buttonHeight and buttonSpacerHeight to ivars
  - removed underscored ivar access in favor of explicit self referencing
  - changed all ivar referencing explicit to self
  - changed butonTitles to NSArray from NSMutableArray since mutability not required (or desired)


Note this pull request is on top of the motion effects pull request