It shall be unlawful (1) for any person or persons to hinder or prevent by masspicketing, unlawful threats or force the pursuit of any lawful work or employment, (2) to obstruct or interfere with entrance to or egress from any place of employment, (3) to obstruct or interfere with free and uninterrupted use of public roads, streets, highways, railways, airports, or other ways of travel or conveyance, or (4) to engage in picketing a private residence by any means or methods whatever: Provided, That picketing, to the extent that the same is authorized under constitutional provisions, shall in no manner be prohibited. Violation of this section shall be a misdemeanor and punishable as such.