MSG and different levels of chattiness

I was thinking this morning about how dillo can either be set to be
extremely chatty or basically silent, and that maybe it would be good
to have some intermediate possibilities.

So here I tried adding a msg_level_min (1-4: 1 for msgs like open_url,
2 for policies like denying redirection or information like creating a
file, 3 for warnings, 4 for dillo errors) :

http://www.dillo.org/test/msg_levels.diff

dillorc makes it sound like show_msg is mostly for debugging, whereas
we use stdout a fair amount for msgs that we want a user to see...

But then there's the fact that maybe no one runs anything from a
cmdline anymore, in which case maybe we should also/instead be logging
to a fltk window that can pop up like the window for html bugs -- or
possibly a widget that can show up in the UI (although the latter might
be brittle and an excessive amount of trouble).