Scope cleanup part 1

Fixes #1099

User visible:
 * Introduced the "Tab", "Selection" and "Comments" views, as per #1091
 * Fixed the following problems:
   * Clicking on a tab does not update scope name
   * Clicking on a highlight does not update scope name
   * Clicking on heatmap does not update scope name

Internal:
 * Change function names:
   * applyview -> applyView
   * applysor -> applySort
 * Move the `view` field from viewer's scope to rootScope
 * The `updateViewer` and `showViewer` methods of the Hypothesis class
   no expect a `viewName` parameter (alongside the list of annotations),
   which they use to update the `view` field of the rootScope.
 * Added a `getComments` RPC call in guest, to collect comments for comments
   scope.

Like #1096, this is an angularjs upgrade issue too, which was already fixed once, so strange.

Fixing the fix for the #1065

Search refactoring 1 - try 2

This does the following:

 * Introduces the `viewFilter` service, to filter annotations according to a given query.
 * Factor out the filtering code from the controller into this new service. (As described in #1092)
 * Enhances the tab searching: now we can search for multiple tags.

https://en.wikipedia.org/wiki/Don%27t_repeat_yourself

It was hiding in the manage_new_data(). It generated the standalone url for the annotations in the old hardcoded way. Fixed.

Closes #1086

Only replace extra slashes with a single slash.

In the previous implementation we did a really unnecessary string conversion.

This solution is shorter and cleaner.
It does fix #1065 however it does not solve the underlying discussion about the document plugins unencoding.

Introducing email notifications to page owners.

Add V1 viewsort feature

The viewsort feature allows users to better control the annotations that appear in the sidebar. The view control allows users to select either SCREEN (in which the sidebar only displays annotations that are currently visible on screen) or DOCUMENT (All annotation on the page are visible in the sidebar). The sort feature allows users to sort annotations by newest, oldest, or location (where they fall in the document). Both controls are implemented in simple tabs below the topbar.

The sort feature is implemented using Angular's very useful OrderBy attribute on ng-repeat.

The view control is implemented using updateviewer.

I had accidentally screwed this up when I combined some CSS in
the past few commits.

Unwrap the "magic controls". It's unnecessary structure that
doesn't save much and this way the style doesn't need to include
a display property. They can be inline or block.

This should have been qualified before, so that it only applied to
the main content header.

A step toward unification, remove the distinction between app and
site layouts.