[BZ 1022943] Ability to trigger update of plugins on agents from UI and API
This is stage 1 of the series of commits to enable more user-friendly
handling of plugin updates.

It provides basic support for triggering updates of plugins on agents
by calling server-side APIs/GUI.
Merge remote-tracking branch 'origin/master' into bug/1022943

Conflicts:
	modules/enterprise/server/itests-2/src/test/java/org/rhq/enterprise/server/test/TestAgentClient.java
	modules/enterprise/server/jar/src/main/java/org/rhq/enterprise/server/agentclient/AgentClient.java
[BZ 1022943] Added ability to check status of plugin update on agents
Merge remote-tracking branch 'origin/master' into bug/1022943

This is to have the fix for BZ 1076389 (which blocks BZ 1022943) in this branch.
[BZ 1022943] Fixes to PluginCriteria
[BZ 1022943] Reporting changes of plugin deployments
note in the javadoc that the deploy* methods are synchronous.
[BZ 1022943] Added a new REST endpoint for working with agent plugins.
Merge master into bug/1022943 reflecting disappearance of plugin purge
[BZ 1022943] Fix delay selection dialog in UI.
[BZ 1022943] Remove remnants of plugin purge from criteria class and REST.
Merge remote-tracking branch 'origin/master' into bug/1022943
[BZ 1022943] Arguments sanity check in ContentHandlerBean#provideAsPlugin()
[BZ 1022943] Correct @PUT and @POST, improve response of register() method.
[BZ 1022943] Don't duplicate the test setup that can be shared.
api checks: adding RemoteInstallManagerRemote.checkSSHConnection() method as intentional non-breaking change
development RHQ_4.12.0-SNAPSHOT
[BZ 1032033] - Sort unavailable & alerted resources portlet - parent first

Unavailable and alerted resources are now ordered by 1. alert count, 2.
ancestry.length 3. resource name - so when for example platform is DOWN it
will show up in portlet before it's children
'upstream/master'.
Let GUI developers assign a tooltip to Table actions
[1093822] RFE: Allow automatic uninventory of dead / missing / removed resources
Initial commit for consideration.  Plugin components can now report DEAD
availability for resources that seem physically removed from the system. DEAD
resources can then be configured for automatic uninventory via a new Admin
GUI view.
[1093822] RFE: Allow automatic uninventory of dead / missing / removed resources
Changing "DEAD" to "MISSING" in response to terminology feedback.