Move extractDefinedIn method into comments.Form.

The form now determines by itself whether to show the definedIn
info or not.
Eliminate #updateComment cfg from commments.Form.
Minor refactoring in the comments.Form template.

Access user properties as subproperties of user.
Remove unused Docs.view.Comments#showMember method.
Rename comments.List to comments.FullList.
Extract Expander and MemberWrap classes.

Move the rendering of class comment counts into cls.Overview class
plus those new classes.
Initial comments.List class.
Extract LargeExpander class.

This will take care of rendering the comments expander together with a
large heading "Comments".  Use in the main comments section of class
and in guides and videos.
Fix crash when switching to comments page.

Forgot to rename selector in controller.
Attempt refactor expand/collapse inside Expander.

Didn't really succeed fully as other stuff in Comments controller
also depends on calling the openComments and closeComments methods.

Crap.
Rewrite of authentication logic.

Created Docs.Auth which performs the actual login/logout stuff.
Docs.view.auth.Form represents the form at the header of the app,
firering "login" and "logout" events.

The Auth controller just binds these two things together - listening
to the events from AuthForm, performing the login with Docs.Auth
and calling back to AuthForm to change how it looks after login.
Move the start of auth init into Appplication#launch.

The Docs.Auth is now observable and fires an "initialized" event
after it's been set up.
Loading of comment counts to API index page.
Show comment counts in class overview page.
Show comments expander in guides.
Show comment counts on video pages.
Show comment counts in guides/videos index page.
Init comments before launching Docs app.

Change Docs.Application to initialize comments before anything else.
This way the rest of the app can rely on comment counts to be
already loaded and avoid setting up listeners all over the place.

Additionally the CommentCounts is now accessed through Docs.Comments
and never directly as it's no more a singleton.
Loading of comments when Expander clicked.

Comments get rendered through the comments.List view.
Restore comment counts in guide/video indexes.

Had gone missing with some previous refactoring.