[MERGE] Bzr diff produces -p1 diffs

[Michael Ellerman]

Hi fellas,

It seems there's a reasonable amount of support for -p1 diffs, so I
went and wrote the patch, it turned out to be _very_ simple. We could
probably use some more test coverage on this stuff.

For the moment I'm just using "a/" and "b/" as the diff headers. I
thought about "orig" and "mod", but that makes the filenames not line
up which looks ugly. We can do something fancier at a later date if
want to, but for 0.8 I think we just want to get the -p1-ness in
there. FWIW, both hg and git use a/ b/ also.

Anyway it's up here, revs 1560 and 1559:
http://michael.ellerman.id.au/files/bzr/diffp1/

cheers