VIENNA (Reuters) - The world-famous Vienna Boys' Choir faces a financial crisis that could put it out of business if it does not reach a deal over the rent for its concert hall and school. The choir, whose roots go back to the 13th century, may have to pay 200,000 euros ($263,000) per year to stay in the Augarten Palace after an agreement for it to use the building rent-free in exchange for renovation work was declared invalid. The Austrian Court of Audit said the deal amounted to an illegal subsidy. ...