Add installation of nistats python package
Add installation of nistats python package

nistats is currently not available on pypi.
Let me know if this is the right place to install it.
For reproducibility purposes we could check out current last master commit `5a3a3ed2cbbb088e558838ea7f2a3b9e7735050a`
ryanlovett/datahub,berkeley-dsep-infra/datahub,berkeley-dsep-infra/datahub,ryanlovett/datahub,berkeley-dsep-infra/datahub,ryanlovett/datahub