New: @accessors section in the Learn Objective-J Tutorial
New: Objective-J 2.0 section in the Learn Objective-J Tutorial

This features sections on dictionary literals, @ref/@deref, and @class/@global
Merge pull request #2 from ahankinson/update-learn-objj

Update learn objj
Formatting.

Refs #2.
Clarify the key functionality of @ref and @deref in the example.