datajam: unify edx-platform and insights virtualenvs
datajam: use depencency versions from edx-platform
Run XBlock workbench as part of datajam.
Merge pull request #508 from edx/brian/add-workbench

Brian/add workbench
Merge pull request #509 from mulby/gabe/datajam/unify-virtualenvs

datajam: unify edx-platform and insights virtualenvs