[Xastir-dev] first cut at geocoder

[Derrick J Brashear]

You can get a prebuilt index from the author of the geocoder, Dan Egnor,
here:
http://dan.egnor.name/all-map.bz2

I haven't integrated the tools to built it yet; The tools are clean but
the process is messy.

http://www.dementia.org/~shadow/xastir-diff.gz

Because I'm not sure this is how people want it to end up looking I didn't
add any langcode tags yet; It inserts itself as a second menu item named
the same as the "Locate Map Feature", and the names of the dialog items
are also reused; It takes ZIP, State, Locality, Address, and path to index
file in that order. If it finds a result it will jump to and center on
that result.

Should I be doing something different with the dialog? If not, I will
clean it up as is (probably reversing the orders of all but the path to
file fields).