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.
Although unrelated to this PR, I find it strange that totaldb.dsy is used by this command instead of the selected dsy from the "Use Signature File" command.