climatology.py: New file - computes and writes climatology files.
  From one point of view, this is a simplified version of plot_data.py
  with some special-purpose features added.  From another point of
  view, this is fundamentally a wrapper around the climatology() function
  which Charles Doutriaux wrote for CDAT many years ago; but it uses the
  new system for searching through files and indexing their contents, before
  reading the data out of them; and various bells and whistles.
filetable.py: Added a flag to override a feature of the file search system,
  where it only picks out "interesting" variables.  The downside is that
  you will pick up garbage variables like date_written.  The advantage is that
  you can index lots of data without figuring out what the garbage is.
  Of course, there's now a function to give you a list of those variable
  names.
reductions.py: new time-only reduction functions for when you don't
  care what the other axes are; good for climatology.