Workflow for Patching Others' Tests

Peter and I discussed this situation last night. While in general we recommend reporting
errors in shepherd, in some cases you might want to propose fixes (i.e. submit a patch
and ask the owner to approve it), because that's more straightforward. The workflow we
imagine is:

   1. "hg copy" the file to your own work directory. (This preserves history.)
   2. Make edits. Commit and push them to the repo.
   3. Ask the owner (or someone else, if s/he is inactive) to review your changes.
   4. If at this point, both you and the owner agree the test is correct, and
      you don't work for the same company, it's been reviewed: you've reviewed
      their work, and they've reviewed yours. So add review links.
   4. The owner/reviewer hg deletes the old copy.

Eventually Shepherd will make this easier with "Fork this test" and "Adopt this version"
buttons, but for now, we'll have to hg copy / hg delete things manually. :)

~fantasai