HTAutocompleteTextField 2.0 development branch

`HTAutocompleteTextField` was created to be as a single-purpose `UITextField` subclass that enables a specific type of text suggestion and autocompletion. Since its inception, however, it has strayed from its original purpose and suffered a bit of feature creep. The intention of this `2.0` release is to right the course, making this library both quicker to understand and easier to use.

With these changes, I am proposing that we link to useful alternate text suggestion and autocompletion libraries (including forks of HTAutocompleteTextField) instead of accepting Pull Requests that alter functionality of this library. In other words, I am proposing that future contributions be in the form of non-functional changes (such as bug fixes, updates to support new iOS SDKs, and refactoring).