Target: Modularity
 - Make m4 optional for build

Target: Robustness
 - Retry submission functionality for long-running sessions
 - Cope with unreported failures (HOW?!)
 - Deal with partial cache flush successes
 - Make lockfile-progs optional

Target: UI
 - ncurses frontend
   * trap WINCH and do something about it
   * fix scrolling
   * at least split the five into one?
   * tuning needs to be supported
   * get rid of all prints that don't use status_msg et al.
 - Multi-threaded operation (daemon a la vux?)
   + Repeat-current-song command
   + Repeat loops
 - libre.fm and others
   + have initial setup offer "other service" and "none" options
   + handle "seamless" tuning of librefm:// vs. lastfm:// radio streams
