Advisory Note Redraft

Friends -

With inputs from several of you, here's a slight rework of that draft 
note for DHS.

Main changes are addition of a brief event description element to the 
example message, and mention of the potential eventually to evolve 
HSAS to a more capable format based on CAP.

Please raise any concerns for discussion with the list in the next 
day or two.  Otherwise, perhaps we can consider this a consensus 
document from the TC and move ahead.

Thanks!

- Art