Bug 835506: Fix error 500 in Download Tab

In Python 2.6, curly brace placeholders used in the str.format() must have an identifier. See http://stackoverflow.com/questions/10054122/valueerror-zero-length-field-name-in-format-python
Corrected typo in Advocating for Web Standards section.
Merge pull request #737 from Nobox/master

Bug 835506: Fix error 500 in Download Tab
Bug 856081 -Redirect /about/drivers to https://wiki.mozilla.org/Firefox/Drivers
Merge pull request #721 from retornam/856081

Bug 856081 -Redirect /about/drivers to https://wiki.mozilla.org/Firefox/...
Merge pull request #740 from lmandel/master

Fix typo in Advocating for Web Standards section. (bug 813198)
Bug 857246 redirect /products/firefox/start/ to start.mozilla.org