Nfldb

======
- Merged PRs 17 and 18. (Methods for determining score of game
at any time.)
- Clocks can now be manipulated by adding or subtracting seconds.
- Fix bug where the `winner` and `loser` properties of a Game
object weren't being set.
- Added the Soundex algorithm to the player_search function.

======
- The "weight" and "height" columns are now numeric.
This is consistent with the change to nflgame to sanitize height data
so that it is all reported in inches.
- In light of the aforementioned change, nfldb now requires nflgame 1.1.23
or newer.

======
- Dummy release because I messed up. No substantial changes.

======
- Don't depend on a specific version of pytz.
- Change `nfldb-update` batch size so that it has a higher rate of
success in lower memory environments.

======
- Fixed city and team name for New York teams.
- Set the cursor factory at cursor init instead of connection init.
(This lets us use an older version of psycopg2.)
- Added an `is_playing` property to games.
- Expose `orelse` in the query interface, even though its semantics
are confusing and unclear.
- Added a `points` convenience method to compute the number of points
scored in a single player statistic.
- Provided a way to update only game schedules with the `nfldb-update`
script. This is useful when game schedules change midway through
the season. Currently, it must be run manually.
- Don't update the DB with drives/plays if none are reported in the
JSON. (In particular, this indicates corrupt JSON while the game
is ongoing, so ignore it.)
- `standard_team` cannot reasonably resolve "new york". It will now
fail with a helpful assertion error.

======
- Don't import errant drives (e.g., a drive without plays).