- update to 0.3.17:
- DOW occurence sharp style support.
- Better test suite
- DST support
- fix bug around multiple conditions and range_val in
_get_prev_nearest_diff.
- issue #69: added day_or option to change behavior when day-of-month and
day-of-week is given
- `Real fix for #34
- `Modernize test infra
- `Release as a universal wheel
- `Raise ValueError on negative numbers
- `Compare types using "issubclass" instead of exact match
- `Implement step cron with a variable base
- convert to singlespec