[Xastir] OpenStreetMaps Update

[Jerry Dunmire]

Curt has committed a new set of patches from me to CVS that should fix
some of OSM problems that have been reported. The new code processes
the scaling/level change when the OSM maps are selected, deselected,
and at startup. The scaling is still binned.

Note, if you are running a previous version of Xastir with OSM support
you will need to delete the OpenStreetMap.geo file. It is typically
installed in /usr/local/share/xastir/maps/Online/. You should also
deselect the OpenStreetMap.geo in the Map Chooser dialog.

The new map file is named OpenStreetMap.osm. Select it to enable OSM maps.

Known issues:
 * The big one is that scaling is not continuous.
    I will be working on this problem next.

 * The map region displayed after an area-zoom may be smaller that the
area selected with the mouse.
    I think this problem will go away with continuous scaling, so I'm
delaying any further investigation until the continuous scaling is
working.

 * OSM support should use tiles rather than OSM StaticMaps.
   I agree and I'm planning on this for a future release.

Let me know about other problems you observe with the OSM support.
Reports that include instructions on how to reproduce the problem are
particularly helpful.

Thank you Curt, Tom, and the other great Xastir developers for your
suggestions and assistance!

73,
...jerry
KA6HLD