Use the repo url instead of assuming the PR repo is the same as upstream
Include repo in candidate_branches
Tried to split up commits, something ended up out of order
Check that merge --info runs for PRs and branches

Note this doesn't check the info is correct, only that it runs without an error.
Fix iteration over self.candidate_branches
Check private status of fork instead of origin
Merge pull request #193 from manics/pr_repo_name

Use the PR repo