Global values in javascript and piwik tracking code moved to a different...

Company specific names now read from settings in javascript. Moved piwik tracking code to a different file so that it's easier to remove by a user.
If you have time, check what happens here with various symbols:
― Django's template system might escape apostrophes, quotes, ampersands etc. to &quot; &amp;. If that renders badly, {{settings.COMPANY_NAME | safe}} should prevent the escaping altogether.
― apostrophe in COMPANY_NAME. The apostrophe should be escaped (\') inside the string literal.
Symbols might not be a theoretical-only case: “Popeye&Son's Yacht Co.”

Otherwise LGTM.