Distinctive icon for labels

Uses http://rrze-icon-set.berlios.de/tango/gallery.html#attribute

[JENKINS-20280] Decide variable overriding order with topological sorting

In this case display the reported exceptions differently and be done with it.
java.lang.NullPointerException
	at hudson.diagnosis.OldDataMonitor.report(OldDataMonitor.java:178)
	at hudson.util.RobustReflectionConverter.doUnmarshal(RobustReflectionConverter.java:312)
	at hudson.util.RobustReflectionConverter.unmarshal(RobustReflectionConverter.java:222)
	at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:72)

[JENKINS-20280] Make it easy to change the implementation. Especially Map.Entry is not so convenient to handle.

Synchronizing XPath-related assertions with implementations in HudsonTestCase, using HtmlUnit’s XPath engine rather than Hamcrest’s which does not seem to work in this context at least.

https://jenkins.ci.cloudbees.com/job/core/job/jenkins_main_trunk/1436/testReport/hudson.model/UpdateCenter2Test/install/
java.lang.NullPointerException: null
	at hudson.Functions$ThreadSorterBase.<init>(Functions.java:1151)
	at hudson.Functions$ThreadSorterBase.<init>(Functions.java:1142)
	at hudson.Functions$ThreadGroupMap.<init>(Functions.java:1163)
	at hudson.Functions.sortThreadsAndGetGroupMap(Functions.java:1136)
	at org.jvnet.hudson.test.JenkinsRule$2.evaluate(JenkinsRule.java:482)

Observed in 1.509.3:
java.lang.NullPointerException
	at hudson.model.AbstractItem.getRootDir(AbstractItem.java:162)
	at hudson.model.Items.getConfigFile(Items.java:236)
	at hudson.model.AbstractItem.getConfigFile(AbstractItem.java:461)
	at hudson.model.AbstractItem.save(AbstractItem.java:456)
	at hudson.model.Job.save(Job.java:152)
	at hudson.model.AbstractProject.save(AbstractProject.java:268)
	at hudson.diagnosis.OldDataMonitor.doDiscard(OldDataMonitor.java:275)

thanks to kutzi for spotting this.

Incorporated Stapler 1.222 to pick up fixes

Conflicts:
	core/src/main/resources/hudson/model/UpdateCenter/RestartJenkinsJob/Running/status_de.properties
	core/src/main/resources/hudson/model/UpdateCenter/body_de.properties
	core/src/main/resources/hudson/model/UpdateCenter/index_fr.properties
	core/src/main/resources/hudson/model/View/sidepanel_cs.properties

Conflicts are resolved in favor of the master branch, assuming people
editing the core is more trustworthy.

This reverts commit b354bca0.

Unfortunately, Afrikaaans is the default selection of the language, and
some people apparently contributed translations without selecting the
proper locale. I see some Hebrew text in here, which was easier to
distinguish because it uses an entirely different character set.

But I have to assume other locales are mixed in here as well.

I'll remove the default language from the translation assistance plugin.
But in the mean time, we don't have anyone who's capable of reviewing
this, so I'm forced to roll back.

(es)

Otherwise a REST API user needs to scan through a couple pages of HTML to find the actual message.

This behaviour is noted in MapOptionHandler.

Optimize and close Zip resources in ClassicPluginStrategy and FilePath