2007/08/11: Instead of storing method state in the method objects (for mode callback stuff), we should probably store it in the buffer. 2007/07/19: Convert all classes to subclass object. 2007/07/19: The minibuffer should be able to expand to become multi-line if the prompt/input string becomes too long. 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.