- command line options for mail_reader and new_mail_notice
- fix up the message counting algorithm
- have glbiff also handle Maildir and MH type folders
- time of day effects: colour of sky, colour of grass, position of light
  source
- more intelligent response when .glbiffrc is missing
- make the fps configurable
- provide command line switches
- general cleanup of the code; a major facelift
- clean up Makefile
- sometimes when opening or closing the mailbox, the camera "teleports"
  for a single frame (highly intermitten; rare)
- do anti-aliasing (really important when the window is small)
- sky colour based on time of day (twilight, dusk, high noon,etc.)
- the point-light imitating the position of the sun
- same with the colour of the point light
- maybe that sign dohickey; in the SGI version there is a
  command line switch which allows you to put a little sign
  on the mailbox (you specify the text string)
- texture for the ground, and mailbox
- perhaps shadows; I haven't figured out how to do a shadow
  onto a Bezier patch (the curvy bit), but should be possible
- some standardized documentation would be good, man page, info page,
  etc.
- better format for the .glbiffrc file
- command line switch for which file to parse instead of $HOME/.glbiffrc 