Faceted and geosearch controller

The search controller now accepts the following combinations:
 * `lat` and `lng` (optional `search` = 'anything`) to list all applications within 5 miles of that location (10 to a page)
 * `lat`, `lng` and `search` (useful examples: water, tree, conditions) to list all matching applications within 5 miles of that location (10 to a page)
 * `authority` (optional `search` = 'anything') to list all applications for the named authority (10 to a page)
 * `authority` and `search` to list all matching applications for the named authority (10 to a page)

At present, specifying lat/lng and authority causes the lat/lng to be used and the authority param is ignored. This may prove to be a mistake if a lat/lng is required to draw a map, in which case it should be easy enough to flip the logic (I've had it both ways around at various points during Friday afternoon). 10 things per page and the 5 mile range may also need adjustment but they're useful placeholders for now.

The setups for category and status filters is included but left commented out until we are in a position to add those in to the data model.

To get the search to work properly, you will need to run `rake ts:rebuild` so that Sphinx knows about geosearch and the authority facets.

**Note** - the authority search uses a facet filter rather than a bounded geosearch

Closes #22

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