Broadway cleaners voted to authorize a strike Tuesday amid negotiations over a new contract.  The strike vote marks the first time the more than 250 cleaners, who are a part of the 32BJ of Service Employees International Union, have voted to authorize a strike in 18 years. Talks with the Broadway League, which represents their employers, the theater owners ATG, Nederlander, Shubert and Circle in the Square, are ongoing, but the Broadway cleaners say the two parties are still far apart on several issues, and the current contract has expired.  The union is asking for wage increases that keep pace with the cost of living, improved pension benefits and healthcare, better working conditions and paid leave and strengthened anti-discrimination measures. The strike authorization vote does not necessarily mean a strike will happen, but gives the union the option to call a strike if necessary, and is often used as a show of force amid negotiations.…