Rdt

This version comes with a brand new API and internal implementation, removing the old
metadata JSON from the user provided arguments, and making each transformer work only
with `pandas.Series` of their corresponding data type.

As part of this change, several transformer names have been changed and a new BooleanTransformer
and a feature to automatically decide which transformers to use based on dtypes have been added.

Unit test coverage has also been increased to 100%.

Special thanks to JDTheRipperPC and csala for the big efforts put in making this
release possible.

Issues

* Drop the usage of meta - Issue [72](https://github.com/sdv-dev/RDT/issues/72) by JDTheRipperPC
* Make CatTransformer.probability_map deterministic - Issue [25](https://github.com/sdv-dev/RDT/issues/25) by csala

New Features

* Add attributes NullTransformer and col_meta - Issue [30](https://github.com/sdv-dev/RDT/issues/30) by ManuelAlvarezC

General Improvements

* Integrate with CodeCov - Issue [89](https://github.com/sdv-dev/RDT/issues/89) by csala
* Remake Sphinx Documentation - Issue [96](https://github.com/sdv-dev/RDT/issues/96) by JDTheRipperPC
* Improve README - Issue [92](https://github.com/sdv-dev/RDT/issues/92) by JDTheRipperPC
* Document RELEASE workflow - Issue [93](https://github.com/sdv-dev/RDT/issues/93) by JDTheRipperPC
* Add support to Python 3.7 - Issue [38](https://github.com/sdv-dev/RDT/issues/38) by ManuelAlvarezC
* Create way to pass HyperTransformer table dict - Issue [45](https://github.com/sdv-dev/RDT/issues/45) by ManuelAlvarezC

* Add a numerical transformer for positive numbers.
* Add option to anonymize data on categorical transformer.
* Move the `col_meta` argument from method-level to class-level.
* Move the logic for missing values from the transformers into the `HyperTransformer`.
* Removed unreacheble lines in `NullTransformer`.
* `Numbertransfomer` to set default value to 0 when the column is null.
* Add a CLA for collaborators.
* Refactor performance-wise the transformers.

* Improve handling of NaN in NumberTransformer and CatTransformer.
* Add unittests for HyperTransformer.
* Remove unused methods `get_types` and `impute_table` from HyperTransformer.
* Make NumberTransformer enforce dtype int on integer data.
* Make DTTransformer check data format before transforming.
* Add minimal API Reference.
* Merge `rdt.utils` into `HyperTransformer` class.

* First release on PyPI.