Rather than using extra events to trigger a round trip through the
visual search directive callbacks and query parsing, simply rely on
$location.search() at the time the route controller is instantiated
and stop using `reloadOnSearch: false` in the route definitions so
that changes to the search trigger a refresh of the view.

The QueryParser now splits `populateFilter` into `parseModels` and
`populateFilter` so that the models can be parsed when the visual
search callback fires and the filter can be populated separately
from the query string after the route reload.

Summary of improvements:

- Drop the VSSearch and RefreshSearch events.
- Make the search.query scope property a simple value instead of a
  function. This reduces the work required for the watcher and is
  possible because we no longer update the query string unless the
  query changes and the route will reload if it does.
- Clearing the stream is no longer necessary, since it starts clear
  on each route reload.