2007/07/17:

It would be nice to be able to toggle various lexing rules on/off, so that for
instance text mode could make spell checking optional, or optionally highlight
URLs/emails/etc.

2007/07/15:

Vertical split would be awesome. Also, need more fine-grained controls for
even horizontally split windows.

2007/07/15:

Rename "lexing" to "parsing" since really we have moved way beyond a simple
lexing/tokenization strategy.