[MERGE] path_content_summary

[Ian Clatworthy]

Rob,

This all looks good (though I'm not sure if there are any cross-platform
issues once we start using it inside commit).

bb:tweak

> +    def path_content_summary(self, path, _lstat=os.lstat,
> +        _mapper=osutils.file_kind_from_stat_mode):
> +        """See Tree.path_content_summary."""
> +        abspath = self.abspath(path)
> +        try:
> +            stat_result = _lstat(abspath)
> +        except OSError, e:
> +            if getattr(e, 'errno', None) == errno.ENOENT:
> +                # no file.
> +                return ('missing', None, None, None)
> +            # propogate other errors
> +            raise

Spelling of propagate.

We have osutils.lstat that falls back to stat on Windows. I'm not sure
if you ought to be using that or not?

Ian C.