More garbage collection.
Merge pull request #47 from ktf/more-garbage-collection

More garbage collection.
Adapt to work with new cms-git-tools.
Merge pull request #50 from ktf/fix-cmspm-v21

Adapt to work with new cms-git-tools.
Backport from V00-21-XX
Merge pull request #52 from ktf/backport-22

Backport from V00-21-XX
Do not even attemp upload if the same parent is already used.