William Shakespeare’s “Macbeth,” currently in the Yard at Chicago Shakespeare on Navy Pier through June 24, is one of the Bard’s most popular tragedies.It is also one of his bloodiest, as it depicts the gruesome tale of the Scottish general whose “vaulting ambition” causes him, with encouragement from his sinister and evil wife, to murder the king and anyone else who might stand in his way to become king himself.It features the Weird Sisters, a trio of witches who gather around their …