Merge branch 'jenkins_19156_windows_processkiller' of https://github.com/synopsys-arc-oss/jenkins into pr903

Resolves https://issues.jenkins-ci.org/browse/JENKINS-19156



Signed-off-by: Oleg Nenashev <nenashev@synopsys.com>

Conflicts:
	changelog.html

correct help text of Label field => can be a Label Expression

https://jenkins.ci.cloudbees.com/job/core/job/jenkins_main_trunk/1065/testReport/junit/hudson.model/ProjectTest/testPoll/

Eliminated the wrong script tag generation from <st:bind/>

(04:07:53 PM) bbeck: In a plugin, given hudson.model.Node object is there an easy way to figure out how many busy/idle executors that node has?  There only seems to be a method to determine the number of executors, but not their states.
(04:24:02 PM) kohsuke: bbeck: see Computer
(04:25:51 PM) bbeck: kohsuke: thanks, just noticed the countIdle/countBusy functions there.

Added another attribute 'checkDependsOn' on <input> elements (akin to
'fillDependsOn', etc) to list up the other dependency controls, and
insert appropriate onchange events.

'checkUrl' is now just the stem portion of the URL to invoke, and
the client script builds up the query parameters.

[FIXED JENKINS-9913] At least print a diagnostic to the build log if we are waiting on a checkpoint.

BuildStepCompatibilityLayer already implements BuildStep, so its subclasses need not say they do as well.

Also [JENKINS-19042] does not seem to have made it into 1.526; seems to have been towards 1.527.

Follow-up on PR #848

The contents of those files are manually inspected.
This will hopefully reduce the ramp-up curve for new users.
This is based on http://www.jetbrains.com/idea/webhelp/project.html

This reverts commit 1a6f3dfa.
forgot to add this file

MAVEN_OPTS=-Dfile.encoding=Cp1252 mvn -DskipTests -f core/pom.xml clean compile