/elec/propeller-clock

* Automatically draw text.

  Text::draw() should be called from propeller-clock.cc, and it should itterate

  over active messages and call draw_message() on them (which does what the

  current draw() does).

  This requires that Text somehow knows which messages are active. Perhaps

  message_reset() could somehow be used to determine this?

  This is necessary so that the cludgy call to Text::post_draw() can be removed

  from propeller-clock.cc. The problem here is that if _do_draw_reset is set

  false inside what is currently Text::draw(), only the first drawn message is

  ever correctly reset!

  This would also make calls to Text::draw() unnecessary from mode draw()

  routines.

  At the same time, remove calls to Text::reset() from SwitcherMajorMode. This

  now be done at the start of reset_messages(), which should be renamed to

  set_up_messages() in all modes.