add leauge wide stats

[double-dose-larry]

maybe have a league object.
league can be MLB, or AL or NL

Then we can have league_season object that holds things like

• Standings
• For batting/pitching/fielding:
  • standard tables
  • value tables
  • there's a whole bunch of other stuff in here
• misc
  • attendance

that's it for now, much more in there