[Grok-doc] virtualenv section removed from grok tutorial

[Jan-Wijbrand Kolman]

Hi,

While updating the documentation for the 1.2 release, I quite bluntly 
removed the virtualenv-related sections from the grok tutorial. I'm not 
sure I wasn't perhaps to blunt.

Could someone review the tutorial and maybe even amend it?

I can certainly make sure any updated is published on grok.zope.org.

Thanks!

regards, jw