TKDO 0.7

  General:
    + Added a curses-based text interface.
    * Updated config library to allow saving only non-default values.
    + Added ability to snooze for units such as 'ddd' (3 days) or 'ww' (2 weeks).
    + Added ability to filter in 'and' or 'or' modes
      (to display a union of contexts instead of an intersection).
    * Made snoozed / completed tasks display as 'Zzz' / '[X]' instead of '0'.
    * Handle missing task files by ignoring them instead of exiting.
    * Added task title to log message for launching the editor.
  CLI:
    + Added an automation facility based on the TUI.
      Basically, any extra parameters will be executed as if the user had
      typed them into the TUI.
  Shared UI:
    * Moved most of the GUI logic into a shared base class,
      so the TUI and GUI can share behavior without writing everything twice.
    + Added a 'zoom' feature to auto-filter into the current branch.
      (bound to the 'enter' key by default)
  TUI:
    + All new curses interface! Works well over ssh.
  GUI:
    * Changed 'editor' config item to 'editor_gui'.
      The GUI and TUI can use different editors.