Cleanup: Remove unused fonts CSS file

It was replaced by the `fontsHead.scala.html` view.

Author: LaCuneta

public/stylesheets/netlogo-fonts.css

@@ -6,8 +6,7 @@
  * It *does not* include code related to
  * - widgets, which lives in widgets.css
  * - widget theming,         netlogoweb.css
- * - fonts,                  netlogo-fonts.css
- * - loading spinner,        spinner.css
+ *-  loading spinner,        spinner.css
  * - code tab syntax,        netlogo-syntax.css
  */