Policy rebind tests
Enricher rebind tests
AbstractMembershipTrackingPolicy: make GROUP a config key
AbstractController’s member-tracking policy tidy

- in preparation for policy persistence
- and same for nginx
AbstractController: use sensor for serverPoolAddresses
AbstractMembershipTrackingPolicy usages not anonymous classes

- sub-class AbstractMembershipTrackingPolicy so that persist/rebind
  could re-create the policy; i.e. not anonymous inner classes.
PR #1415 policy persistence: incorporate review comments
Merge pull request #1415 from aledsage/feature/policy-persistence-20140523

Prep for policy persistence