Moved QSL Bureaus list to CallsBureaus.xml and added
CallsBureaus.GetBureau method to retrieve the QSL bureau for a
callsign.
Modified various classes to retrieve bureau using
CallBureaus.GetBureau rather than classes in QslBureaus.dll.
Modified AboutDialog class and App class to remove QslBureaus.dll
version from AboutDialog and the runtime info logged in the log file.
Removed the Qsos, QsosTests, QslBureaus, and QslBureausTests
projects and file as they are no longer used.
The Qsos and QsosTests projects were removed from the solution as part
of the changes for issue #21, but the files had not been deleted.
QslBureaus and QsoBureausTests projects were removed as part of the
changes for issue #123.
This completes changes for issue #123.