Beginning of support for multiple fair maps

This is handled by convention at the moment.

For a map to display we require:
1. an image (located in `/images/maps/#{FAIR_ID}.png`)
2. a map transformation function, keyed to the same ID, located in `/utils/maps/coffee`.

If a map is unavailable, detected based on the presence of its transformation function, then we skip all map related logic in the view and don't display anything.

Also includes test coverage for the the map utilities.