[Pydotorg-redesign] Sidebar/nav. bar revisions

[A.M. Kuchling]

Here's another round of sidebar changes:
    http://www.amk.ca/python.org.html

The "mirror sites" link has been moved down.  SIGs and Help have been 
dropped from the top navbar, replaced with a "Contact us" page (still 
to be written) and "Site map".

Comments?

Secondary issue: given the current plague of viruses (and the 
likelihood of future viruses), should we be trying to minimize the 
number of times e-mail addresses are given on web pages?  The 'Contact 
us' page would be a step toward this: this single page would be the 
only ones with an e-mail address.

--amk