After five years of getting the runaround from the Metropolitan Transportation Authority, the Durst Organization has said enough is enough. The developer is suing the MTA over the prolonged discussions involving its three properties at Park Avenue and East 125th Street, alleging that the public transit authority’s slow decision-making, lack of diligence, changing stances and failure to cooperate have cost the company money and deprived it of its rights to use the properties. The lawsuit,