Move weeks listing into display_seasons_weeks()
Make future week check more pythonic

I wasted an hour on this, debugging a problem where datetime would throw
an error /only/ after the addon had been run once...

http://forum.xbmc.org/showthread.php?tid=112916

I don't know what the real problem is, but I think it's a Python bug.
Bumping xbmc.python to 2.14 (for Gotham) did not help. :-/