Merge branch 'jc/push-follow-tag'

Merge branch 'jc/push-follow-tag'

The new "--follow-tags" option tells "git push" to push relevant
annotated tags when pushing branches out.

* jc/push-follow-tag:
  push: --follow-tags
  commit.c: use clear_commit_marks_many() in in_merge_bases_many()
  commit.c: add in_merge_bases_many()
  commit.c: add clear_commit_marks_many()