Performance enhancements for corncob and betta
This minor release adds functionality without changing the content or format of the outputs (with the exception of adding the wald statistic to the corncob and betta outputs).
- Corncob is now run across multiple shards
- Added the wald statistic to corncob and betta outputs
- Set the maximum pickle protocol to 4 for backwards compatibility with python < 3.8
- Added validation of corncob output, including pickle protocol 4 and python 3.7