* Add Zpk2tf function
* Add zpk2tf function documentation
* Fix
* Add freqz function implementation
* Fix format
* Add freqz function documentation
* Fix
* Fix format
* Update index.d.ts
* Fix Dependency error
* Fix
* Fix index.d.ts
* Fix Documentation
* Fix Lint
* Fix index.d.ts
* Fix The Matrix parameter support and index.d.ts
* Fix Format
* Add Unit Tests for Matrix cases
* Fix Docs and Lint
* Add tests for coverage
* Fix Format
* Update AUTHORS
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Co-authored-by: Jos de Jong <wjosdejong@gmail.com>