[aprssig] New MSG-OBJ format (rev b)

[Bob Bruninga]

> Still think POI would be better -- It saves three letters 
> POI for short as this is 7 keypress on my TH-D72...

Disagree. "OBJ" is only 6.  And it is an APRS object we are talking about,
there is no such thing as an APRS POI. 

> ...but if the symbol is optional, then it must be delimited.

Agree.  [/$] is optional and must be after the object name and before the
text.

Proposed Spec updated:  http://aprs.org/aprs12/msg-obj.txt

Bob, WB4APR