Add models for Home Owners Associations and Cases

Fixes #3.  Includes:
- `BOACase`, `HomeOwnersAssociation`, and `TMAPCCase` models
- Django admin models
- Management methods `load_hoa`, `load_boa_cases`, and `load_tmapc_cases`
- Fixture with strings corrected (`./manage.py load data bps-2014-08-24`)

There are still a number of import issues, because the GeoDjango LayerMapping doesn't have a lot of flexibility:
- Management commands import new objects, rather than looking for existing data to update
- The string `\/` is directly imported, rather than being converted to `\/`
- Dates are imported as strings rather than being converted to dates.
- Assuming that case dates are the hearing dates, but hard to confirm
- Some HOA items have no geometry
- The HOA attributes `Id` and `Umbrella` are not imported, because they don't appear to have interesting data
- The HOA data does not include contact information
- Some items have bad data, such as the TMAPC case type `PUD Site Plan\r\n\r\nPUD Site Plan'`, requiring cleanup

I'll add these as post-prototype issues


And all of this diff-checking and case-updating code too. Looks like it could go into a single `create_or_update_case(attr, domain, case_type)` function?