CODING STANDARD POLICE
sketch of the advanced search method
Tweak advanced_search query handling

* remove fuzziness from the query_string (it's not supported)
* handle boolean properties properly
* for single value terms, don't wrap the filter in an array
Correct conversion from page/per_page params to from/size query
Allow for pagination in clients, return total with results
add world locations
add index name to the logging output
formatting
tidy up mappings

using strings as we now use slugs
Add tests around ElasticSearch#advanced_search

Tidy up the implementation while we're at it.
Test the return value of advanced_search

It's not just an array of documents, so we should be explicit about it.
Test the app.rb implementation of advanced_search