Created basic elasticsearch node
Added additional sensors
Added config keys required for clustering
Added support for elastic search cluster
Fixed (and simplified) clustering, using automatic zen discovery
Updated following PR review
Updated following PR review, added integration tests
Group notified on member unmanaged

- and member notified on group unmanaged.
- done automatically, without need for registering listeners.
- will be generalised to “relationships” at some point.
Deprecate DynamicGroup.stop
Deserialize: discard dangling ref in ImmutableSet

- If didn’t then it would fail to deserialise, which would cause 
  entire file to fail to deserialise.
  The dangling ref will have been logged plus handled by the 
  RebindExceptionHandler, so mostly harmless ignoring it here.
Fix logging on Effectors.invoke
Tidy QuarantineGroup.expungeMembers
entitlements scheme proposal

add EntitlementsTest
record entitlement context for REST web requests, and log more info of web requests
add AcmeEntitlementManagerTest
add isEntitled check to ApplicationResource and EntityResource
add unauthorized to WebResourceUtils
add FROM_ENTITY function to EntityTransformer
add EntitlementPredicates
address review comments for #23
rename hasEntitlementClass to isEntitled
This closes #23
entity tags support, including REST API (but not GUI)
fix entitlements failing test
This closes #26
restore the removed `Os.isAbsolute`, for compatibility, but marking it deprecated in favour of `Os.isAbsolutish`