Xcsf

Changes:
* Accept 1-D flattened Python inputs in fit/score/predict ([81](https://github.com/xcsf-dev/xcsf/pull/81))
* Fix setting max trials via JSON ([83](https://github.com/xcsf-dev/xcsf/pull/83))
* Remove Python `seed()` and add `RANDOM_STATE` parameter for setting seed ([86](https://github.com/xcsf-dev/xcsf/pull/86))
* Major Python API update: sklearn compatibility ([77](https://github.com/xcsf-dev/xcsf/pull/77))
* Add Python callback support with EarlyStoppingCallback ([77](https://github.com/xcsf-dev/xcsf/pull/77))
* Add parameter to read initial population from JSON; also works in stand-alone binary now ([77](https://github.com/xcsf-dev/xcsf/pull/77))
* Add hyperparameter tuning example ([77](https://github.com/xcsf-dev/xcsf/pull/77))
* Add CheckpointCallback ([88](https://github.com/xcsf-dev/xcsf/pull/88))

Changes:
* Fix deserialization of tree-GP and DGP conditions ([74](https://github.com/xcsf-dev/xcsf/pull/74))
* Update libraries ([75](https://github.com/xcsf-dev/xcsf/pull/75))

Changes:
* Add support for pickle to Python library ([72](https://github.com/xcsf-dev/xcsf/pull/72))

Changes:
* Add defaults to Python API calls to allow a cleaner syntax ([60](https://github.com/xcsf-dev/xcsf/pull/60))
* Fix an input check on the cover parameter in predict/score ([60](https://github.com/xcsf-dev/xcsf/pull/60))
* Update Python cartpole example to latest version and refresh other examples ([60](https://github.com/xcsf-dev/xcsf/pull/60))

Changes:
* Add an optional argument to the Python predict/score functions that specifies the value to return for a sample if the match set is empty instead of invoking covering ([59](https://github.com/xcsf-dev/xcsf/pull/59))

Changes:
* Add docstrings and variable names to Python library ([43](https://github.com/xcsf-dev/xcsf/pull/43))
* Fix minor memory leak when printing parameters ([44](https://github.com/xcsf-dev/xcsf/pull/44))