May 8 (Reuters) - Former world number one Vijay Singh sued the PGA Tour on Wednesday, a week after golf's premier tour dropped a doping a case against the three-times major winner. Singh was initially found by the PGA Tour to have breached the sport's doping rules after using a spray, which contains a banned substance, to treat an injury but was later cleared of any wrongdoing after winning an appeal. He filed a lawsuit in the Supreme Court of the State of New York on Wednesday, and issued a statement saying the PGA Tour had damaged his reputation. ... More...