Display a message that the comments are powered by Disqus.

This is useful when JavaScript has been disabled for Disqus, but enabled
for the host domain. Otherwise the visitors get no indication whether
comments are present or not.
removed python 3.2 because markupsafe explodes with it
new nikola check --clean-files option
Ensure output/assets/css exists before creating code.css there
fix typo (missing parenthesis)
Merge pull request #506 from yarko/master

fix typo (add missing parenthesis)
updated translations
Merge pull request #505 from notfoss/disqus-fix

Display a message that the comments are powered by Disqus.