Changed the documention to be relevant to Tavern.

Recompiled the CSS from mustache files so that 'Tavern' is displayed
instead of pub in most locations.

Updated the help pages to remove unapplicable 'pub <x>' targets.

Updated help pages to show how to upload using pub.

R=tapted@chromium.org

Review URL: https://codereview.appspot.com/56910048