[Python] pip over proxy (e.g. behind a firewall)

pip install --proxy http://[<usr_name>[:<password>]@]<proxyserver_name>:<port#> <pkg_name>

You might want to upgrade pip while you are at it.

python[.exe] -m pip install --proxy http://[<usr_name>[:<password>]@]<proxyserver_name>:<port#> --upgrade pip