I think this better ensures #1135 is fixed cleanly. Before, the
controls might hide after the timeout, but the user may be on their
way to click it. Now, everything goes through showViewSort, and it
manages timeout cancellation.

Also, moved the view and sort controls out to the app.pt. Because
they're essentially global now, and we should move to kill the viewer,
editor, search distinction anyway.

Also, use destructuring while we're here for readibility

Coffee always breaks switch cases

Moved `applyView`, `applySort` and `viewState` to the root scope.

Fixes #1131.
Fixes #1132.

Fix #1123

Multiple selections

The way to avoid it is to just handle the view switch entirely in
the sidebar, rather than consulting the heatmap, if comment view
must be activated.

Improve CSS for viewsort controls

Pressing Ctrl (or Compose), and clicking on a highlight,
or a tab on the heatmap now adds annotations to the current selection.
A second such clicks removes them agian.

k