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. Add support the the second type of weatherxml (see man page).

4. There are a few remaining document types that we need to parse
   before "version one point oh." This list refers to an
   old proprietary implementation, sorry:

     * Schedule_Changes_XML

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

   * Cbask_Indv_No_Avg_XML.dtd
   * Cbask_Indv_Shooting_XML.dtd
   * CBASK_StealsXML.dtd
   * Cbask_Team_Scoring_Rebound_Margin_XML.dtd
   * Cbask_Team_Scoring_XML.dtd
   * Cbask_Team_Shooting_Pct_XML.dtd
   * NFLGrassTurfDomeOutsideXML.dtd
   * NFLInterceptionLeadersXML.dtd
   * NFLPassingLeadersXML.dtd
   * NFLReceivingLeadersXML.dtd
   * NFLRushingLeadersXML.dtd
   * NFLTackleFFLeadersXML.dtd
   * NFLTopKickoffReturnXML.dtd
   * NFLTopPuntReturnXML.dtd
   * NFLYardsXML.dtd
   * NFL_PuntingLeaders_XML.dtd

6. 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):

   * AutoRacingDriverList
   * AutoRacingGridXML
   * CBASK_Individual_Stats_XML
   * Cbask_Roster_XML
   * cbaskteamschedulexml
   * CBATeamScheduleXML
   * CFLTeamScheduleXML
   * CFLTotalTeamScheduleXML
   * earlylineXML
   * Minor_Baseball_TeamScheduleXML
   * MinorLeagueHockeyTeamScheduleXML
   * MLB_Boxscore_XML
   * MLB_earlylineXML
   * 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