improve logging for longevity tests
refactor EntityCleanupLongevityTest so that (1) it checks explicitly that things have been cleaned up, (2) we have a unit test as well as a long-running test, and (3) the long-running test makes memory assertions; currently explicitly excuses certain leaks (which we want to patch soon)
reply to code review comments, method now called `isMostlyEmpty`
Extract BrooklynLauncherRebindTest from BrooklynLauncherTest
Adds high availability management-plane support

- support for standby management-node(s), where one is automatically promoted
  to master when the current master fails or terminates
REST api: high-availability / management-plane queries
add configuration for rat plugin
Merge pull request #1365 from olamy/rat-plugin

add configuration for rat plugin
Adds MultiLocation
Deprecate SimulatedLocation

- because will be moved to tests, from main
Merge branch 'feature/locations-as-availability-zones' of https://github.com/aledsage/brooklyn into review
Merge branch 'feature/managementNode-warmStandby' of https://github.com/aledsage/brooklyn into review
Tests DynamicCluster serviceUp is set correctly
convenience utils for strings and enums
use fields in CLI for persist and HA; rename high-availability option to highAvailability; and set default HA to auto, reverting to default if persist is off
comments and code tidy from #1366
use explicit for-tests mgmt context in CliTest so it runs much faster
Merge pull request #1366 from aledsage/feature/locations-as-availability-zones

locations as availability zones
replace the redundant HighAvailabilityManager.StartMode with HighAvailabilityMode
add `isRunning()` to HAManager to distinguish between HA disabled-pseudo-master and HA active-master