Add unique field to message classes - EUCA-6069

Add groovy local AST transformation for creating a synthetic UUID field
on compiled classes. Groovy message source files now use a package
annotation so UUIDs are added and the compiled classes do not conflict
according to JiBX rules.

EUCA-6069
Merge remote-tracking branch 'origin/dev/sjones/EUCA-6069' into maint/3.4/testing