No longer compiling against HA & JGroups; using reflection to introspect HA status. Main advantage is that this works even when running from a proxy WAR (otherwise there are class loading issues). Secondary advantage is that it makes the plugin much smaller: avoids shipping two copies of JGroups in jenkins.war.
[RM-1522] Use JGroups 3.2.0, which includes a fix for the annoying JGRP-1538 (chatty logging).
Make it easier to run the HA proxy WAR against a JE WAR using another version of HA.
The --daemon option to the proxy WAR was not working.
Suppressing chatty message: Elected as a backup node in null
Bundle Jetty (and vietnam4j) only in those components which actually need it.
Do not show content other than the warning when inactive; otherwise get NPE from HAStatus.getNodes etc.
High availability is not available on Java 5 due to lack of support from the underlying JGroups library.