This is pretty much a direct port using the *almost* exact same
form definition file, except:
1. Uses sbbs.dll for common functions
2. Read config file (main.ini), so now needs SBBSCTRL env var set
3. Some minor improvements, like hour-glass cursor while searching
   and re-reading/loading/displaying the user data when any changes
   are saved.
4. Supports the v3.20 user base (obviously)
5. Flags nodes in-use by modified users with the UDAT node flag

Some old bugs (e.g. the user credits were read/written from the old/wrong
byte-offset) are no longer relevant.