Add non-graphical V6 support to Dumb interface
Dumb Frotz, as originally created, was capable of playing V6 games by showing the outlines of where the graphics would go. This is where the Curses interface acquired its capability of doing this. When Dumb Frotz was incorporated into the Unix Frotz repository, this ability to do this was lost when Blorb functionality was introduced. In the interest of completeness, I would like to add to the Dumb code the ability to access image data through the Blorb library. Currently all the Dumb interface does with Blorb is provide access to a Zcode chunk.