BLD Add enum34 and mock package if python 2 as it is now a requirement for pymc3.
BLD Add enum34 and mock package if python 2 as it is now a requirement for pymc3.

ChinaQuants/pyfolio,YihaoLu/pyfolio,chayapan/pyfolio,femtotrader/pyfolio,ChinaQuants/pyfolio,femtotrader/pyfolio,quantopian/pyfolio,YihaoLu/pyfolio,quantopian/pyfolio