Added a patched version of jzlib from
https://github.com/kohsuke/jzlib/tree/jzlib-1.1.3-kohsuke-1 to better
understand the deflate problem.

Implemented the hook

Integrated the fix in Stapler.

[JENKINS-19622] Merged #989: allow background tasks to run simultaneously, preventing task blockage.

CLI hits "/cli", so the server needs to respond to this endpoint.

Hold on to the lease until the very end.
Previously, the lease was only held until the main build section is over, before publishers start running.

noting this change after the fact.

If slaves are late to come online after a Jenkins startup, we will see a huge spike of builds as Jenkins attempt to get a workspace for polling.