Sort dicts by their keys to get a stable representation.

[icemac]

No description provided.

[viktordick]

Huh, this conflicts with #116 , where I planned to drop the whole str_repr function because absent support for Python 2 it became equivalent with repr. If I am not mistaken, this function is never called with dicts, the meta contents prepared in zodbsync.py already have dicts converted into sorted lists of tuples.

I have no objection to keeping str_repr around for this corner case, but I would like to understand where you encountered the situation that a dict is passed into str_repr.

[icemac]

@viktordick We had dicts of dicts as values in our local object_types.py. Refactoring this to tuples of tuples makes this PR obsolete.

Thank you for pushing me into the right direction.