Merge branch 't-prove-target' into pu

* branch t-prove-target:
  t/Makefile: add a "prove" target
Merge branch 'dedent-commentary' into pu

* branch dedent-commentary:
  Dedent comments when adding them to merge messages
Merge branch 'add-option' into pu

* branch add-option:
  Add "--add=<branch>" action
Merge branch 'pass-no-log-to-merge' into pu

* branch pass-no-log-to-merge:
  Pass --no-log to git-merge explicitly