[ANN] graft plugin

[Jamie Wilkinson]

This one time, at band camp, John A Meinel wrote:
>Thanks for writing this. I may have a specific use for this, since I did
>just convert a project that was in both CVS and Arch. The biggest
>problem for me is that the two branches were synchronized periodically.
>So I would both have to find the common ancestor, and figure out how to
>handle when they were merged.

Yeah, that's trickier :)

I did start out writing support for grafting a limited range of revision on
a branch, but never got around to incorporating it into the plugin.