cleaned up imports and re-organized SimpleALViewPropertyArray

- Moved UIKit and Foundation imports into prefix header
- Renamed a method in the NSLayoutConstraint category for consistency
- SimpleALViewPropertyArray_InteralArray ->
  SimpleALViewProperty+ArrayManipulation
   - seems a bit more clear since you're just allowing someone
     else to manipulate the array
   - eliminates the need for an addObject method
- Renamed createArray method and added block typedef for clarity
  in NSArray+SimpleAL