Add installation instructions for Ubuntu.
Add installation instructions for Ubuntu.

albanD/lunatic-python,hughperkins/lunatic-python,bastibe/lunatic-python,bastibe/lunatic-python,alexsilva/lunatic-python,albanD/lunatic-python,greatwolf/lunatic-python,greatwolf/lunatic-python,hughperkins/lunatic-python,alexsilva/lunatic-python,alexsilva/lunatic-python