TODO

   1 - [ ] optional text wrap
   2 - [ ] write
   3 - [ ] caching (use cache by default, unless explicitly asked for update)
   4   - [x] value --> cache
   5   - [x] value <-- cache
   6     requires: commands
   7 - [ ] timeline limits
   8 - [ ] feed set operations (perhaps better done externally?)
   9 - [ ] timeline as a result of a query (feed set op + filter expressions)
  10 - [ ] named timelines
  11 - [ ] config files
  12 - [ ] parse "following" from feed
  13   - following = <nick> <uri>
  14 - [ ] parse mentions:
  15   - @<source.nick source.url> | @<source.url>
  16 - [ ] highlight mentions
  17 - [ ] filter on mentions
  18 - [ ] highlight hashtags
  19 - [ ] filter on hashtags
  20 - [ ] hashtags as channels? initial hashtag special?
  21 - [ ] query language
  22 - [ ] console logger colors by level ('error)
  23 - [ ] file logger ('debug)
  24 - [ ] commands:
  25   - r | read
  26     - see timeline ops above
  27   - w | write
  28     - arg or stdin
  29     - nick expand to URI
  30   - q | query
  31     - see timeline ops above
  32     - see hashtag and channels above
  33   - d | download
  34   - u | upload
  35     - calls user-configured command to upload user's own feed file to their server
  36   Looks like a better CLI parser than "racket/cmdline":
  37   https://docs.racket-lang.org/natural-cli/