MOSCOW (Reuters) - Allegations by a former head of Russia's drug testing laboratory that dozens of Russian athletes used doping when they competed at the 2014 Sochi Olympics are "slander by a turncoat" and are absolutely groundless, the Kremlin said on Friday. Russian presidential spokesman Dmitry Peskov told a conference call with journalists the Kremlin supports comments by Russian Sports Minister Vitaly Mutko that the allegations by Grigory Rodchenkov, the former laboratory head, are "nonsense". ... More...