Fix diff bug

[NitefullWind]

No description provided.

[coveralls]

Coverage decreased (-28.4%) to 71.629% when pulling 7b7c958 on NitefullWind:patch-1 into 0c222a9 on dsoprea:master.

[bystrzak]

This fix does not work when the path provided is poinitng to a single file. I worked it around with

            if diff_summary['path'] == full_url_or_path:
                file_name = full_url_or_path.split('/')[-1]
            else:
                file_name = diff_summary['path'].split(full_url_or_path)[-1].strip('/')
            if file_name in file_to_diff:
                diff_summary['diff'] = file_to_diff[file_name]

[idbrii]

Neither of those fixes repositories with file:// urls (no exceptions, but the summaries have no diff despite the files being modified).

I'm doing something like this:

 os.chdir(os.path.expanduser('~/svn/checkout'))
 pprint.pprint(client.diff('HEAD', '', '.'))
 pprint.pprint(client.diff('HEAD', '', 'file.txt')) # this file is modified

For file:// repositories, neither diff has a 'diff' element.

For https:// repositories, the '.' version has diffs, but the 'file.txt' one does not.

[dsoprea]

This should be resolved in the latest release. I've reimplemented it. Since the shape of the output has changed, I also bumped the major number on the release. I apologize for the shoddy implementation. This was contributed by someone else and not checked carefully enough.