Merge branch 'stable'

* stable:
  Release notes for 2.1.2.4
  Update JGit to 0.7.1.34-gf36df5d to fix empty tree bug
  Add 'checkout' download command to patch sets
  documentation: Document Read Access +2 aka Upload Access
  documentation: Elaborate on branch level Owner
  Fallback to ISO-8859-1 if charset isn't supported