- fix `str.isnumeric` #605
- fix `WeakSet` `KeyError` #548, #553, #596 -> #607
- stop `tqdm_notebook` description truncation #582 -> #599
- include `unit_scale` for `rate` #608
- add `auto` -> nowarning `autonotebook`
- add better postfix numeric formatting #621
- minor refactoring #609 -> #616
- update documentation
- add unit tests
- fix py26 CI