Added `DynamicMultiGroup` entity.
added CLOUD_MACHINE_NAMER_CLASS ConfigKey to allow custom machine naming
Added CustomMachineNamer
Addressed PR comments
/applications/createLegacy returns wrong Location

JAX-RS specifies that the Response.created(URI) is relative to the
request URI, in this case /v1/applications/createLegacy. This means that
the created Location: header looked like
/v1/application/createLegacy/123456, which is incorrect. Changed method
to build an absolute URI so that JAX-RS does not try to change it.
Fix failures in ApplicationResourceIntegrationTest

Jersey resource tests seemed to get very confused when trying to use the
application create endpoint that takes byte[] and tries to autodetect.
Changed to use the explicit 'createLegacy' endpoint instead.

Sensors come back in the format `"stopped"` but test was looking for
`stopped` without quotes - fixed.
Address code review comments:
- Add descriptions to config keys.
- Don't modify shared EntitySpec instances.
- Remove unnecessary bits.
- Always run test setup.
- Strengthen assertions about member sets.
Wrapping variables to avoid errors when the path contains spaces.
More code review fall-out:
- defensively copy Entity sets before creating iterator
- rename convenience methods (now childrenOf, membersOf)
- tidy-up concurrent map declaration / initialisation
Expose the JmxFeed builder created by JavaAppUtils connectMXBeanSensors

Allows entities to call getMxBeanSensorsBuilder and add further polls
without having to create a second JmxFeed. The existing behaviour of
connectMxBeanSensors is unchanged. Deprecates `times` in favour of
the functions in brooklyn.util.math.MathFunctions.
Don't attempt to rebind to existing applications in BrooklynLauncherTest

Test was failing because I had persisted entities that were not on the
test's classpath.
Merge pull request #1252 from sjcorbett/expose-jmx-feed-builder

Exposes JavaAppUtils' JmxFeed builder and fixes test in BrooklynLauncherTest
Added interfaces for dynamic loction support
Merge pull request #1243 from grkvlt/feature/dynamic-locations

Added interfaces for dynamic location support
Merge pull request #1254 from jdtoy/spaces_in_paths

brooklyn launch vs. spaces\ with\ paths
Merge pull request #1248 from richardcloudsoft/fix/ApplicationResourceIntegrationTest

Fix ApplicationResourceIntegrationTest
Merge pull request #1230 from Nakomis/custom-machine-naming

added CLOUD_MACHINE_NAMER_CLASS ConfigKey to allow custom machine naming
More code review and tidy-up:
- Trivial tidy-up: sensor creation.
- Annotate @Beta
- New entity predicates: isChildOf() and isMemberOf()
- Switch from ENTITY_PROVIDER to ENTITY_FILTER.
- Renamed GROUP_SPEC to BUCKET_SPEC, for clarity.
Fix edge case of a bucket being removed the re-added.
Don't refer to an entity's display name after it has been unmanaged.