Generate legacy .dmr files on demand, remove .dmr files for core subsystems
Get rid of all .dmr files for subsystem tests
Reinstate susbsystem test controller for 7.1.2 and turn on via system
property. Also fix reading reading dmr model description for 7.1.x
Merge pull request #10 from kabir/generate-legacy-dmr-on-demand

Subsystem test framework tweaks
[WFLY-2512] Remove unused ExplicitTransformationDescriptionBuilder
[WFLY-2512] Unused code in ResourceTransformationContext(Impl)
[WFLY-2512] Chained resource transformer support
[WFLY-2512 Chained operation transformers
[WFLY-2512] Expose subsystem version from SubsystemRegistration
[WFLY-2512] Use proper ResourceTransformationContext impl for model-test and subsystem-test
[WFLY-2512] Enable placeholder registrations for subsystems
[WFLY-2512] Make the placeholder registry behave exactly the same as GlobalTransformersRegistry
temp Break JMX transformers, revisit