[Xastir] GNIS data

[Jason KG4WSV]

Even before the GNIS format changed, I thought I'd covert them to
shapelib so I could use a dbfawk (instead of source code changes) to
control how they're drawn.  Never found sufficient free cycles to
execute that plan.

Maybe there's some way to extract some useful information out of the
new GNIS data, and keep population data from the old GNIS files, or
even get population data from somewhere else.  Note I haven't looked
at the new GNIS data to see if this even makes sense...

-Jason
kg4wsv