The city has revoked the permit for the condo tower being built at 303 East 51st Street, the site of the March 15 crane collapse that killed seven people, because of zoning violations. The project, between Second and First Avenues, has been stopped since the accident. James P. Kennelly, the developer, can apply for a new permit or appeal the decision to the Board of Standards and Appeals. Forty-six claims have been filed against the city over the accident, seeking nearly half a billion dollars. Meanwhile, the family of a crane operator killed in the May 30 crane collapse on East 91st Street said they planned to file a lawsuit.