All persons concerned in the commission of a crime, whether it be felony or misdemeanor, and whether they directly commit the act constituting the offense or aid and abet in its commission, or, not being present, have advised and encouraged its commission, or who, by fraud, contrivance, or force, occasion the intoxication of another for the purpose of causing him to commit any crime, or who, by threats, menaces, command or coercion, compel another to commit any crime, are principals in any crime so committed.