feat: further improvements

[Berkmann18]

• More (sorted) data
• Updated chart
• Better tests
• More insight into the data
• More possible ways to use the Learner
• Playground for demonstrations
• Improved confusion matrix colouring and printing

[Berkmann18]

:tada: This PR is included in version 1.2.0 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket: