[aprssig] Preliminary delayed packet analysis

[Stan - N0YXV]

Thanks Steve for the simple "There is no single point where such a
collection could be made, the dup filtering happens at every stage."
answer...that's all I wanted to know. :-D Sometimes it takes somebody to
point out the painfully simple answer for the "No Duh" factor to go off in
ones' head. I'll shut up now and go hide in my little corner again. :-D