Redesign and optimize the API

NOTE: This commit includes a number of breaking changes to the API.
- Introduce the 'auto' prefix to all public methods, and a new 'al_' prefix to all private methods. This insures against namespace issues and potential conflicts that could arise.
- Introduce a new category on NSArray which offers modified versions of the old methods on UIView that add constraints to arrays of views. These methods are also now more resilient, such as if the array includes other objects besides UIViews.
- Re-organize some private internal methods.
Update tests for latest version of API