Fix many bugs with the Symbols menu (when run with -d argument).

The Symbols menu is now fully useable.
A much more complete dsy file is included, called combined.dsy.
Generate the Symbols then use the combined.dsy file to identify far more functions.
I was thinking that the two menu items would be "Load map file..." and "Load other map file..."   How you have it here is "Load other map file..." and "Load bad map file..."