[MERGE] Implement guess-renames

[Jelmer Vernooij]

Aaron Bentley wrote:
> This patch implements a guess-renames command.  Assume some other
> process has renamed some of your files.  This will guess what renames
> were performed and update bzr accordingly.
>
> The main use-case for this is when importing from tarballs, but renames
> from mv, nautilus, or random other utilities are also supported.  It is
> completely acceptable to modify the content of the renamed file, so long
> as it retains a significant resemblance to the last-committed version.
> The algorithm for files uses edges (sequential pairs of lines) for
> matching, so that single matching lines do not trigger a match--
> matching *sequences* of lines are required.
This seems like a very useful addition.

This might also be useful as an optional implicit action before commit, 
perhaps depending on some option in .bzr/branch/branch.conf.

Cheers,

Jelmer