Hello!

Sorry for the delay, I took the time to remember why I did it that way. I didn't want to alter the templates too much and the highlighting is handled by two code paths depending if the code is from code cells or markdown fenced code blocks. That's why I ended up putting similar traits in two places. The ultimate idea was to place two more traits (again!) to rule them all, at the application level.

To de-duplicate these traits, I would need to pass `resources` from the template on to the highlight2html filter or to alter the templates. I don't mind, its easy to do! I just don't want to mess things up (thus adding the traits in Highlight2Html circumvented my worries).  

I would go with propagating `resources` to the concerned filters to preserve the templates - even though instead of asking the highlight function not to highlight, the template should simply not call the highlight function. I just get that itchy feeling that the `resources` object could actually be needed by potentially many filters and, you know, the urge to unify filter calls :)

For the moment: `resources` as a kw argument for just the filters who need them?