Added a test, which sets up a job and verifies that the build state is set to unstable.

Conflicts:
	src/test/java/plugins/PmdPluginTest.java
ADDED TEST
- run_on_online_slave_and_master_with_node_restriction
Fixed installation of newer plugins.
[JENKINS-23004] Start AD plugin test(s) => 1st scenario; usage: javadoc.
Fixed installation of newer plugins.
Fixed installation of newer plugins.
Fixed installation of newer plugins.
Adapt to changes of @WithPlugin.
Improving the logic to detect the need for restart.

This avoids a lot of unnecessary restarts
Adding groovy as a dependency
Adding groovy console support to assist the test development
adding a mechanism to export local variables
Use the same set of cookies so that it sees the same thing Selenium sees
introduced useDeltaValues and changed assertTrue to assertThat
Merge branch 'ldap' of https://github.com/eidottermihi/acceptance-test-harness
[JENKINS-19614] Added a test case that tries to expose the bug.
Merge branch 'nlp_schulze' of https://github.com/sschulzeHM/acceptance-test-harness
Document Since
Added TODO.
Desperate attempt to fix findElement timeouts