[aprssig] Validation Code

[scott at opentrac.org]

> Umm, maybe WinAPRS is not updated as regularly as some would 
> wish, but UI-View cannot be updated at all, the source code 
> has been destroyed at the request of the late author. Only 
> add-on modules can be created and updated.

Not true!  I made a 3-byte modification to UI-View32, and it only took me
about 4 hours without the source code!  =]

Scott
N1VG