TODO

Things to do (critical, no order):
- Modify the screen code for adding text to use an extended buffer when
  combining characters are used, and add functions for directly adding a
  character with combining characters.
- Modify the selection stuff to clear the visible selection (but not
  the buffer) when only a portion of the selection is modified...
  Possibly don't bother with the case where the entire selection is modified,
  but definitely don't clear if the selection area isn't modified.
- autotools or other automagical make system
- Implement lots of unimplemented escapes
- Find some way to let the glyphcache be shared among like-fonted temu widgets
- Track down some screen clearing problems, reproduce and fix.
- Track down some screen reset problems, reproduce and fix.

Things to do (non-critical, no order):
- Support more of the attributes that are already set in the code in screen-xft
- Add IMPL()s to some impremented escapes that are missing them
- Possibly write a plain X renderer (distant future)
- Figure out scaling for non-scalable fonts
- Make scaling an option
- Allow resizing width/height of the font
- Figure out how to handle text properly when it goes outside its cell
- Speed up renderer (on-going)
- Clean up scrolling/scrollback.