Fixed creating css on Windows and removed absolute paths from css

- Forced UTF-8 to be ran on all of the sass files, without this webfonts were broken due to charset changes
Merge branch 'front-end' into autobahn_v1

Conflicts:
	master/buildbot/status/web/files/css/default.css
	master/buildbot/status/web/files/sass/modules/page-elements/_tables.scss