Log Message:
Import reposurgeon-2.12 as devel/reposurgeon.

A tool for editing version-control repository history reposurgeon
enables risky operations that version-control systems don't want
to let you do, such as editing past comments and metadata and
removing commits. It works with any version control system that
can export and import git fast-import streams, including git and
hg and bzr. It can also read Subversion dump files directly and
can thus be used to script production of very high-quality conversions
from Subversion to any supported DVCS.