prepared 1.2.1 release
prepared 1.2.1 release

MDPvis/rlpy,silgon/rlpy,rlpy/rlpy,imanolarrieta/RL,BerkeleyAutomation/rlpy,BerkeleyAutomation/rlpy,rlpy/rlpy,silgon/rlpy,MDPvis/rlpy,rlpy/rlpy,silgon/rlpy,BerkeleyAutomation/rlpy,MDPvis/rlpy,imanolarrieta/RL,imanolarrieta/RL