In order to upgrade clean-css it is necessary to import the filter
definition from the future version of webassets. This version takes
extra arguments in the filter configuration, allowing us to disable
the advanced optimizations that became the default in 3.0+ but that
breaks some of our styles.

Fix #2452

This lets the top bar set a font size for its inner content while
still matching the padding to the rest of the page.

This is much neater. Since the scale origin is the center of the
icon this will scale around the center of the line, avoiding any
messy vertical alignment nonsense. This works much better than
vertical-align middle and font-size because vertical-align middle
puts the center of the element at the x-height, rather than the
middle of the line. This is much cleaner.

Lay out the search bar and the top bar using flexbox because the
vertical centering is much better and easier using flexbox instead
of floats and line heights.

As long as we're using only features easily supported in the 2012
and final spec the -ms prefix gets us IE10. All other browsers we
care about should be supported already by the compass mixins.

- Use .btn wherever we use .btn-clean

- No border on .btn-clean

This is necessary for true vertical alignment.
See http://christopheraue.net/2014/03/05/vertical-align/

- Convert some units to ems

- Remove extraneous rules

- Remove extraneous integer parts of floats

Fix https://github.com/hypothesis/h/issues/2429

Oops

Replace the use of the websocket for scrollback with a simple
pagination scheme.

Rather than having a fixed body that scrolls, let the body take a
natural height and rewrite the infinite scroll handler to watch the
global scroll.

The infinite scroll directive is now smarter and has tests.

New version released has a my fix for height 100% html and body tags.
Restores scroll-to-annotation in PDFs.

This makes the code easier to understand because it makes explicit
the relationship to the line height of the label.

Close #2421

This change simplifies the AnnotationSync events and improves the
frame symmetry by giving the guest its own AnnotationSync setup
function, alongside its AnnotationUISync setup, that mirrors the
way its handled in the widget.

Previously, the `loadAnnotations` and `deleteAnnotations` events
were treated specially by AnnotationSync so that it didn't cause
endless loops. Instead, fully embrace the fact that the guest is
not responsible for loading or deleting annotations.

- Remove the setupAnnotation and deleteAnnotation methods, as they are
  no longer used.

- Factor out everything but the event publication of deleteAnnotation
  into a detach method that is the inverse of the anchor method.

- Subscribe to annotationsLoaded and annotationDeleted and invoke anchor
  and detach accordingly.

Like all the other calls, this should invoke its callback.

This ensures there's a digest cycle on the angular side after
the client state is synchronized and brings this into symmetry
with the other RPC calls defined by AnnotationSync.

This causes unnecessary network traffic and momentarily blanks the
ephemeral properties of the annotation set on the client.

Make setupAnnotation into a tiny compatibility wrapper around a new
method #anchor() method that returns a promise of the anchors. This
is cleaner than trying to store the anchors on the annotation itself,
which creates circular references, and it means there's no need to
strip these properties when serializes annotations across the frame
boundary.

Sort annotations by TextPositionSelector in the widget display. This
provides greater visual stability -- cards don't change positions
after anchoring -- at the cost of potentially out of order cards when
anchors have moved.

We're not displaying time in any timezones other than the browser
local one. Therefore, we don't need to parse and convert time zone
names. Moment will pull the timezone offset itself from the current
browser by using Date.prototype.getTimezoneOffset().

This eliminates 251kB (43kB gzipped) of minified code from our
application bundle. Wow!

The new choice is simpler. It does not deal with scrollable elements
below the window. On the other hand, this also makes it less liable
to choke on edge cases when scrolling the window would be just fine.

This becomes necessary as a result of the change introduced by
mozilla/pdf.js@b1c4b85d4fb7faba2b454d02d279644244bf282b

This method has existed for a long time so hopefully this won't
cause breakage for anyone on a slightly older FF.

It is included just fine by the require statements.