Improve thread collapsing UX.

- Keep the namespaced classes sorted by file
- Keep the collapsed annotation overrides in the annotation file
- Improve the vertical alignment of the timestamp better
- Make margins and elements go away in the collapsed state rather
  than using negative margins to hide them
- Simplify the thread expander styles

Topbar toolbar harmony

Fix guest embedding

To prevent an Annotator is undefined error, the constructor class is set
by the object returned from the hypothesisConfig function. The documentation
has also been updated.

When the search icon is clicked give focus to the search input.

Harmonize the styles of the buttons in the top bar and the toolbar.

- Match font size of icons at 18px
- Buttons are .btn-clean and have minimum width so icons are square
- Transitions for background color
- Simplify the styles for the top bar, using the newly consistent
  clean top bar button styles instead of specific styles for the
  share button.

- Threads collapse to single lines.
- Use iconograpy consistent with collapsing / expanding UI in other
applications
- Threads are fully expanded when you click replies on a top level annotation.
- Delete old test and add new tests.

Add ability to share via links from the sidebar.

Use of {{angular templates}} causes problems on pages with Annotator
enabled due to Annotator's habit of splitting text nodes whenever you
select anything. Specifically -- if you select one of the words in this
text and then change the privacy setting, it will end up rendering as
something like

   PubliOnly Me
   Only Melic

or similar. Using a span tag and ng-bind is a bit of a hack but it
prevents this from happening.

Oh, Angular...

Make annotation visibility level more explicit

- Private annotations have the word private as well as the lock icon on the card
- Small styling refinements have been added to make the annotation-license
- Show the word private alongside lock icon.
- Show message explain visibility setting when editing.

Small ux improvements

- Use document plugin to get canonical url for sharing.
- Introduce Topbar share icon
- Add social media icons to icomoon
- Generate via uri in the share-dialog directive
- Add sharing via Facebook, Twitter, Google plus, and email
- Make account dialog and share dialog consistent
- Add information about sharing to the help page.
- Add tests (Thanks @nickstenning!)

Report form level errors

When we call `form.validate()` and the validation fails, the raised
exception is a `deform.ValidationFailure`. This object has an `error`
attribute which represents the underlying validation error object for
the entire form.

Previously, if the validation failure were a result of top-level
validation errors (such as the fact that an unactivated user is trying
to log in), this error would be lost, because we only reported errors
for the forms fields, or "children".

This commit changes `h.accounts.views.validate_form` so that it converts
the entire `colander.Invalid` object into a dictionary using its
`asdict()` instance method. By doing this, we get two immediate
benefits:

- top-level validation errors are reported in the '' (empty string)
  field
- we avoid the need to aggregate form field errors by hand in ajax_form

In addition, we need to deal with this case on the frontend, so this
commit also changes the formRespond directive so that if no overall
"reason" is provided for failure, then an empty-string member of the
"errors" object can set the overall validation status (and error
message) for the form.

Refactor search

Ask for "Username or email address" when logging in

Fully isolate os.environ during config testing

Dehorusify the AuthController

Keep app css and inject css separate

Structure is good. Bonus fewer false dependencies on asset rebuilds
for the app.

Dehorusify ProfileController

Fix display regression on help/first-run pages

Let users change their email addresses

1. Go to the Change Your Email Address form
2. Type in a new email address (twice) and your password
3. Select part of the text showing your current email address with the
   cursor
4. Click Update

=> The display of your current email address is updated to a nonsense
value.

This commit fixes the issue, your email address will be displayed
correctly.

Move the user's current email address out of the placeholder attribute
of the new email address <input> field. Just put it in a <p> instead.
This is much better for usability.