SERENGETI-1883: Fix SCA warnings, compiler warnings and clean up imports
DE5833: Create capability to remove event duplicates for event types that should be exclusive. Unit tested and buddy-checked by George
DE5836: Refactor out getActiveTTs so that it can be called as a public function from EDPolicy
DE5831: Clear the mapred.hosts.exclude file and refresh to enable newly powered-on VMs to automatically join...
Stale mapred.hosts.exclude doesn't affect us anymore...
DE5836: Putting back earlier version of "checkTargetTTs" since the recent one does not check repeatedly
for correct TTs in all cases.
Merge branch 'master' into model

Conflicts:
	elastic-runtime2/src/main/java/com/vmware/vhadoop/vhm/ClusterMapImpl.java
	elastic-runtime2/src/main/java/com/vmware/vhadoop/vhm/strategy/BalancedVMChooser.java
Adds the new getActiveTTs method into the Model hadoop adapter and
supporting code into Serengeti