[releng] Fix duplicate content parser registrations
[unrelated] Add MappingCall to QVTc
Merge remote-tracking branch 'upstream/master' into working
- Added the ColorNode example metamodels
- Added the QVTc examples of the ColoredTree
- Fixes to the Test Class to implement the doTest method called by all
other test methods
- Implemented the code to validate the models against an expected result
- Applied the patch to support recursive mappings