Improve DynamicFabric test coverage

- for when fabric has existing children
DynamicFabric: add existing children as members
Adds EntitySpec.groups and EntitySpec.members
Reworks BrooklynRestApiLauncher

Makes it much simpler to launch servers in any context, with whatever
security provider you want, custom filters and with or without the jsgui.
add tips for using & abusing RAT
ignore target when running rat
Alters logging in BrooklynPropertiesSecurityFilter to not read request body

.. at least before the chain has been processed. Adds an integration test
to verify that the interaction between the filter and FormMapProvider
works as expected.
Adds failing test in BrooklynNodeRestTest to WIP group
Tidies getUser functionality in jsgui and quietens jsgui build
Miscellaneous tidies
This closes #97
Adds integration test for ServerResource.getUser
This closes #98
This closes #82
deploy / undeploy / update on the ControlledDynamicWebAppCluster
tidy initial pull request from @bmwshop, as per code review, plus some todo comments
move deploy and redeploy bodies to DynamicWebAppCluster, with ControlledDWAC calling to that,
and with new interfaces for the shared items (deploy effectors etc) so that ControlledDWAC is not a JavaWebAppSoftwareProcess
better tasks logic for deploying wars when target entity is ready (ie service up), failing gracefully if it's not, with some helpers in Tasks and DynamicTasks
squash code warnings, clarify user-facing messages, fix redeployAll bug
have at-entity tasks show up as children (in dynamic queueing context, though still submitted externally which means they will not be run as part of queue), and allow them to have children: improves traceability in GUI when effector methods call other effector methods, they show up as children rather than background tasks (or worse, not even as background tasks); and support setting flags in TaskBuilder