don't make loofah add linebreaks

1d9e6366 introduced loofah html sanitizing.

As a side-effect this pretty-prints the html which conflicts with our html+single-linebreaks formatting.

Deep-divin into Nokogiri docs turns up an option to not format the outputted html:

https://nokogiri.org/rdoc/Nokogiri/XML/Node/SaveOptions.html Found here: https://github.com/sparklemotion/nokogiri/issues/233#issuecomment-145009

Fixes fdroid-website#247 (closed)