[aprssig] Test program using MapSource Maps

[BH]

I've made 2 changes to the program.  I added a "MAPS" link in order to
show you which map sets are available and to select between them.
There are currently 12 map sets loaded, from the World map to Hawaii
Topo maps.  Clicking the MAPS link will show which set is currently
the active set.  Click on any of the set links in order to select that
set as the active map.  Secondly, I have decoding of compressed
packets working for Lat/Long and symbol, other parts of compressed
packets are not yet decoded.

KH2Z