TREFF: Add a hidden country field for when we support multiple countries
TREFF: Convert all use of Lat/Lng to pure addresses

Converting to/from address was introducing noticeable errors. Also, the end-user
has no sense of what lat/lng means, only addresses, so it makes sense to keep everything in addresses.
This does mean more storage, but SQL table storage is relatively cheap.
TREFF: Cleanup js function files
TREFF: Implement directions finding based on starting address and midpoint address