v0.8.0

• Added support for upgrading to Jenkins 2 from Jenkins 1
• Added support for installing pinned plugins from multiple update centers
• Significant improvements to Groovy script error reporting
• Added ability to configure multiple admin users (jenkins_admin_sids), and to
  configure users with CLI access independently of them being admins
  (jenkins_cli_users)
• Added significant updates to Jenkins configuration for
  Kerberos, LDAP/basic auth, backup configurations, and
  more
• Added oneshot Jenkins backup playbook for cases where cinch will run on
  existing Jenkins masters created without cinch
• Updated Jenkins repo URL
• Added ability to exclude changes to Jenkins plugins+configuration
• Added configurable NTP server support
• Added ability to install packages on both master and slave with single var.
  This renames the additional_packages var to jmaster_extra_rpms to be
  consistent with the existing jslave_extra_rpms, and adds a new var called
  extra_rpms for use in the jenkins_common role.