Remove unused NoteModel
Change custom Backbone.ajax function

It turns out that you can set the dataType and not have to make your own
custom function to fetch incoming data.
Move makeURL over to it's respective model
Add parse function to dynamically load `full_text`
Simplify click event inside of view
Bind togglePreview to this

Also url, but this is mainly so it can be called after the content being
fetched can call its callback with no problem.
Merge branch 'model-fetch'