Database setup

Here's a database file that the application can start with, containing tables for location entries (as discussed in #1) and favorites, plus ~20MB of data from [GeoNames](http://download.geonames.org/export/dump/) cities_1000.txt that we can use for some simple reverse geocoding. We might add tables/columns to the database during development, in which case we'll decide whether to write code to handle the migrations or just make the changes by hand on our own databases. Sound good?

I'm also including some initial code to interact with the database, but don't have that 100% working -- so don't merge just yet.