chore(main ReadMe): check and improve
improve(Introduction): Update and rewrite
improve(testing-basics): add setup and teardown documentation
improve(unit-test): Update and include full example
docs: update
docs(testablejs): update
docs(bdd): add bdd page
docs: update testing vocabulary
docs: update
docs: update bdd and tdd
improve: remove ui test, update structure
docs: add exercises