No env3 about tf-coriander

[yarrseni]

You have to create a virtual environment, for particular one yo've mentioned, it would be

`mkdir -p ~/env3/

cd ~/env3

virtualenv venv`

You could read more on Python virtual environments here: py-docs/venv

[Whytehorse]

OK, thank you. I didn't need to use a virtual environment. Perhaps the instructions could be updated to show that is optional and add the steps you mentioned.