Install pacakges via pip locally
PYTHONUSERBASE is now CMAKE_INSTALL_PREFIX installing in Externals led to subsequent packages not finding pip installed modules, because PYTHONPATH not set properly. And it didn't make sense to spread the python packages in so many places
Final attempt to fix path for pip installed packages
Ok very last edit to get pip working
Merge remote-tracking branch 'dev/fix_pip_installed_packages'