Expose Port 8000 for easy manual testing

Add ``serve`` module as a command line subcommand which enables us to start a server within the docker environment.
This is helpful in testing the ``pyodide`` builds running within the docker environment using external browser
programs of the same machine.

Handle multi-line Python strings input in JS

Fix package loading race condition

Add NetworkX Package

Reduce the number of mandatory imports in matplotlib

Package scikit-learn

Fix #261: Support named arguments when calling a JS function

Scipy packaging

Fix #254: Continue if package loading fails

Fix Chrome Tests failing inside Docker

Support a baseURL passed on window.languagePluginUrl