the stable branch and a minor issue

[Holger Freyther]

Hey,

please only use fast-forward commits (no git-push --force) for the stable 
branch. Not doing this will create an issue for our autobuilders.

We have this issue. If we build a specific revision which gets "orphaned" (no 
one is referencing is) and people do a fresh checkout/clone they will not get 
this revision or with a git-gc this revision will be garbage collected.

z.