configure: consolidate dependencies in one pkg-config call

Makes it easier for unexperienced contributors to patch configure.ac
Adding Piracicaba to Locations.xml.in

https://bugzilla.gnome.org/show_bug.cgi?id=707603
[TO BE REVERTED] Unmark a string for translation

String freeze is in effect, will mark again for 3.13.1
Changing ICAO of Piracicaba for an airport that has METAR data.

https://bugzilla.gnome.org/show_bug.cgi?id=707603