Avoid issues in test-env when trying to register MBean, since Plexus dispose() is currently called once per-test-class
Avoid issues in test-env when trying to unregister MBean, related to other change
Merge pull request #725 from sonatype/safer-mbean-registration

Safer handling of mbean registration
Add support for -Dtest.debug and -Dit.debug flags which will enable DEBUG (or other specific levels if configured) for test[suite] logging
Merge remote-tracking branch 'origin/master' into nexus-5472-proxy404
NEXUS-5472: New IT that tests "wl transitioning"
NEXUS-5472: Using Caches client subsystem.

Add testsuite client caches subsystem
as shorthand and using it instead of doing
hacks