* Move frame gathering into error code path (PR [34](https://github.com/click-contrib/click-option-group/pull/34))
* Fix typos (PR [37](https://github.com/click-contrib/click-option-group/pull/37))
* PEP 561 support (PR [42](https://github.com/click-contrib/click-option-group/pull/42))
* Update docs dependencies and Travis CI Python version matrix (PR [43](https://github.com/click-contrib/click-option-group/pull/43))