Add @Exported annotation to the executor of a Run to have more information on a running Job via the remote API

This is based on https://github.com/jenkinsci/jenkins/pull/521

I'm not entirely sure if the reparse point should be considered the same as symlinks, but I'm merging this anyway.

If the user has an earlier Jenkins installation,
we should probably change the jenkins user shell
during the upgrade.

If the user has already changed jenkins user shell
to something else, we do not touch it.

notify user some results have been truncated
provide link to get more results

Uninstall.command is dropped to /Library/Application Support/Jenkins

Used xmllint --format

Noticed via failure in BuildCommandTest.testConsoleOutput.
https://github.com/jenkinsci/jenkins/pull/522

Note that http://netbeans.org/bugzilla/show_bug.cgi?id=197335 displays this incorrectly.

Rather than patching configure.jelly, safer and clearer to directly adjust ToolInstallation/global.jelly.

Fixed a problem in actually making concurrent builds work.

This prevents the section title from getting hidden by the breadcrumb
bar.