Quick consistency scan of js.

- Add _id as data attribute to story post.
- Generally prepping for 'edit post' story.
Revive date picker.
Make datepicker a txt box instead of a big div.
Separate post editor from post tab view.

In preparation for using the same editor to edit posts.
Save session token in cookie and auto-login.
Fix broken CKEditor references.
Post model 1st draft.

- New posts saves to server via backbone's .save()
- 'Edit Post' functionality under construction
- other loose ends hanging about...
Factor out alert, 1st pass.
Alerts work more than once.
Fix remaining POSTs to use JSON payload (body) instead of Form.
Handle success/fail on backbone model save when posting.
Edit post modal shows up on double click.

Now functional though ...

- wrote but didn't test server-side edit post
- modal shows
- some view refactoring
    + moved element assignments closer to module definitions.
    + optimized element assignment with this.$el.find
Populate editor with current values.
Add edit button (non-functional).
Login: Autofocus username txt, submit on enter.
Edit button makes modal appear.
Merge branch 'edit_post'

Editing working in the most basic form.
Needs some polishing up, but most of the potentially destructive work
is done, so merging back in.