- error handling
  - probably should be able to initialize the escape code trie with a lot more
    options, and optionally disable them if the terminfo capability doesn't
    exist
  - some output capabilities can also be emulated if the capability doesn't
    exist
- the builtin backend should be able to attempt to dynamically load
  libcurses.so if it sees a terminal or capability it doesn't recognize
  this is probably blocked on rust/#458
- character-by-character trie traversal
- rgb colors
- line drawing
- scroll regions
- mouse?
- windows support? only for hexes, probably