1. Re-enable DTD validation once
   https://github.com/UweSchmidt/hxt/issues/15 is fixed.

2. Write a test for test/xml/Odds_XML-long-import.xml once it no
   longer takes 10 minutes to import (Postgres only?).

3. We have DTDs but no sample XML for the following SportInfo types,
   which have therefore been left unimplmented for now:

   * CBASK_StealsXML.dtd

4. The following DTD types were handled (in some form) by the old
   FeedGrabber. They are not yet handled by htsn-import (some may not
   be valid):

   * AutoRacingGridXML
   * CBASK_Individual_Stats_XML
   * Cbask_Roster_XML
   * cbaskteamschedulexml
   * CBATeamScheduleXML
   * CFLTeamScheduleXML
   * CFLTotalTeamScheduleXML
   * Minor_Baseball_TeamScheduleXML
   * MinorLeagueHockeyTeamScheduleXML
   * MLB_Boxscore_XML
   * MLB_IndividualStats_XML
   * MLB_Probable_Pitchers_XML
   * MLB_Roster_XML
   * mlbteamschedulexml
   * mlsteamschedulexml
   * NBA_Boxscore_XML
   * NBA_Individual_Stats_XML
   * NBA_Roster_XML
   * nbateamschedulexml
   * NCAA_Basketball_Boxscore_XML
   * NCAA_FB_TeamScheduleXML
   * NCAAHockeyTeamScheduleXML
   * NFL_Boxscore_XML
   * NFL_CompBox_XML
   * nfldepthchartxml
   * nflteamschedulexml
   * nhlteamschedulexml
   * WCBaskTeamScheduleXML
   * WNBA_Boxscore_XML
   * WNBA_Individual_Stats_XML
   * WNBATeamScheduleXML

5. Consolidate all of the make_game_time functions which take a
   date/time and produce a combined time.

6. Factor out test code where possible; a lot of them differ only in
   the filename.

7. Combine test XML files where possible.

8. Remove the -XDeriveGeneric argument in test/Doctests.hs; it
   shouldn't be necessary if doctest picks up the LANGUAGE pragmas on its
   own.

9. Once generics-sop releases support for bigger tuples, we can remove
   the deriveGeneric stuff from Generics.hs. This should also fix the
   doctests.