Features
* Implement use of column expressions for certain validation types by rich-iannone (https://github.com/rich-iannone/pointblank/pull/2, https://github.com/rich-iannone/pointblank/pull/3)
* Reduce dependencies by subdividing them into optional dependencies by rich-iannone (https://github.com/rich-iannone/pointblank/pull/4, https://github.com/rich-iannone/pointblank/pull/5)
Docs
* Add examples for validation methods by rich-iannone in https://github.com/rich-iannone/pointblank/pull/6
**Full Changelog**: https://github.com/rich-iannone/pointblank/compare/v0.1.0...v0.2.0