Set the following in the modopts.ini [avatars] section:
msghdr_draw_top (default is true)
msghdr_draw_above (default is true)
msghdr_draw_right (default is true)

Set any of these to false to override the default behavior -
for DesotoFireflite (VALHALLA).

This commit also includes a couple of changes I've been apparently
sitting on:
- display avatars even for non-ANSI/non-CP437 terminal users
- cache the smbdefs.js in bbs.mods.smbdefs (I don't recall why)