[StGIT PATCH 0/4] Optimizations for the DAG appliedness stuff

The DAG appliedness series incurred a serious slowdown when it had to
recompute the set of uninteresting commits from scratch. (This is the
set of commits that are parents of patch commits, but not ancestors of
any patch commit. They are used to make DAG appliedness operations
fast.)

The patches in this series fall into two categories:

  * Making the recomputation-from-scratch (slightly) faster.

  * Reducing the number of situations where the
    recomputation-from-scratch has to be done.

-- 
Karl Hasselström, kha@treskal.com
      www.treskal.com/kalle