Added AdifEnumerations.xml containing enumerations for Ant_Path and
Arrl_Section. Added classes AntPath, ArrlSect, AdifEnumerations, and
AdifEnumerationsTest.
Added code to App.xaml.cs to read in AdifEnumerations.xml. This is
currently not called.
Added new constructor to EnumerationField and also
EnumerationField.IsDeprecated. Added tests to EnumerationFieldTests.