Change formatting

Make matplotlib optional

Fix matplotlib requirements

Move to poetry+black

Switch to poetry+black

Small fix

Final docstring touches

Hotfix

Merge branch 'master' of https://github.com/piotr-machura/cartesian-genetic-programming

To and from raw

Update README.md

Decoding

Better file saving

Moved example to a new folder

Nodes now remember what they already calculated

Changed example values to correct ones

Working prototype

The example has been added to the package (it will be moved once I
figgure out the proper way to import things). The evolve function has
been moved to a separate file, more concurrency was added in the
specimen methods.

Basic concurrency

The fit is now assigned to specimen in separate concurrent threads.

Function table is now a private, inner class

Raw specimen tuple is now a nested, private class.

It ensures that the from_raw method only processes valid tuples. Also a
stub of the decoding method has been created.