[FIXED JENKINS-13695]

Preserve in-progress builds when reloading a job.
Because in-flight builds tend to update the state a lot, with this
change we refrain from reloading those builds from the disk.

This should be acceptable since we are primarily reloading a job, and
reloading of builds are secondary.

All top-level jobs show up in search, as opposed to just jobs in the
current view or in the primary view.

This reverts commit ebc6af72.

The actual meat of the change is in remoting.

I couldn't quite find one place to do this, so it's spread apart
somewhat.

I should have known better than reusing the version number. Apparently
the issue isn't just in Maven.

Stack trace:

org.jvnet.hudson.reactor.ReactorException: java.lang.IllegalAccessError: tried to access method hudson.security.SecurityRealm.findBean(Ljava/lang/Class;Lorg/springframework/context/ApplicationContext;)Ljava/lang/Object; from class hudson.security.LDAPSecurityRealm$LDAPUserDetailsService
  at org.jvnet.hudson.reactor.Reactor.execute(Reactor.java:246)
  at jenkins.InitReactorRunner.run(InitReactorRunner.java:43)
  at jenkins.model.Jenkins.executeReactor(Jenkins.java:885)
  at jenkins.model.Jenkins.<init>(Jenkins.java:790)
  at hudson.model.Hudson.<init>(Hudson.java:81)
  at hudson.model.Hudson.<init>(Hudson.java:77)
  at hudson.WebAppMain$2.run(WebAppMain.java:217)
Caused by: java.lang.IllegalAccessError: tried to access method hudson.security.SecurityRealm.findBean(Ljava/lang/Class;Lorg/springframework/context/ApplicationContext;)Ljava/lang/Object; from class hudson.security.LDAPSecurityRealm$LDAPUserDetailsService
  at hudson.security.LDAPSecurityRealm$LDAPUserDetailsService.<init>(LDAPSecurityRealm.java:419)
  at hudson.security.LDAPSecurityRealm.createSecurityComponents(LDAPSecurityRealm.java:369)
  at hudson.security.SecurityRealm.getSecurityComponents(SecurityRealm.java:398)
  at hudson.security.HudsonFilter.reset(HudsonFilter.java:134)
  at jenkins.model.Jenkins.setSecurityRealm(Jenkins.java:1960)
  at jenkins.model.Jenkins$17.run(Jenkins.java:2524)
  at org.jvnet.hudson.reactor.TaskGraphBuilder$TaskImpl.run(TaskGraphBuilder.java:146)
  at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:259)
  at jenkins.model.Jenkins$7.runTask(Jenkins.java:874)
  at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:187)
  at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:94)
  at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
  at java.lang.Thread.run(Thread.java:680)

When managing instances with lots of jobs, the size of the view
configuration screen becomes huge because there is one line per job on
the instance.

Going beyond this requires CSS animation.

... since they didn't go to RC.

Previously, the presence of the xpath parameter suppressed the tree
parameter processing. This change fixes that so that the tree parameter
can be used for building small DOM, then XPath to manipulate the data
further.

Added test whether the currently checked slave computer actually can take the buildable item before flagging it as needed (avoids powering up and connecting to slaves for jobs they can't build).