Added Hale tutorial, updated README

Summary of Changes:
Added a Tutorial

Cleaned json in spec
Rewrote section on render
Now supports "enctype" and "request_encoding" as two separate fields
Changed "enctype" default
Cleaned up text for "options"
`search_term` is not specified in the data here. I presume the understanding is that it can be a parameter with any value and that the `state` parameter is constrained. Is the way HAL or we discussed things make this clear w/r to templated URIs that don't have a `data` element definition?