[aprssig] OpenTracker !DAO! support and enhanced resolution

[scott at opentrac.org]

Finally managed to get a couple of items off of my to-do list... the latest
OpenTracker firmware (53940) supports the !DAO! enhanced position resolution
format described in the APRS 1.2 draft spec.

The !DAO! extension adds 5 bytes to the position report and gets you an
extra digit for latitude and longitude.  I'm not sure what programs, if any,
support the extension so far.  I tried it in Xastir and couldn't see any
difference.

The extra digit is also being used in Base91 calculations now, so you have
another option that's better-supported and more compact.  Works great in
Xastir, more than adequate to handle a WAAS-capable GPS receiver.

I had to cut some stuff out to make room, but I realized that all along it's
been parsing the month and year from the GPS date, and I've never found
anything to do with that data.  So that's gone, and now I've got a whopping
97 bytes of free program space to burn!  Woohoo!

Anyway, the firmware's available for download now, just hit the 'load
firmware from web' button in the config program.  Base91 will take advantage
of the extra resolution automatically, but to turn on DAO you'll need to get
the new config program at http://n1vg.net/opentracker/downloads.php.  It
adds a DAO checkbox on the right side, next to the compressed option.  Yeah,
the screen's getting crowded... I'm going to rework it as soon as I have
time.

Scott
N1VG