Ensure only active tiles are returned

[lennym]

Adds a clause to the neo4j query on tile search that checks that the "active" property on the tiles is true.

I don't know if this is the best or most efficient way of doing this - I've not worked with neo4j before so this contains a fair chunk of guesswork - but based on my local tests it seems to work.

Local test as follows:

search.tile({
  includedIn: ['geo:geonames.2510769']
}, (err, results) => {
  console.log(err, results); // should not include 'tile:article.geo.spain.golf'
});

[lennym]

Ignore this anyway... it needs to be an INTERSECTION or whatever the neo4j equivalent is, not a UNION.

Back to set theory 101 for me...

[lennym]

Some time later... this should be ready to go now.

The tests need a wholesale refactor, but that is a separate issue I think.

[tomgco]

LGTM