Add trends, other global goodies

This turned into a bit larger of a pull request than I'd hoped because there's a few infrastructure pieces (layout, real tests) that got bundled in here. 

TODO:
- [x] Test the function that spits back counts
- [x] High-level end-to-end testing (not sure of what form)
- [x] Make sure the address page 404s rather than erroring if there is none
- [x] PEP8-ify everything
Presumably this corresponds to a column name in the existing database, but: what does common_name actually mean?