Bazaar Survival Guide updates (darcs, hg)

[Ian Clatworthy]

A few days ago, I asked a few community members privately to help with
the documentation that eases the transition to Bazaar from other tools.
I'm pleased to announce some nice improvements along those lines:

* for Darcs users -
http://doc.bazaar-vcs.org/migration/en/survival/bzr-for-darcs-users.html

* for Mercurial users -
http://doc.bazaar-vcs.org/migration/en/survival/bzr-for-hg-users.html

Thanks for Miklos Vajna and Paul Moore respectively for their work here.
If you're familiar with these tools, please take a look at these
documents and suggest fixes/improvements as appropriate.

If you want to grab the branch and submit a merge proposal, the project
is lp:bzr-migration-docs.

Ian C.