Re-enable Behat tests for Filelist and Imagelist

[bobdenotter]

I've disabled the tests for these in #815. We need to re-enable them.

@I-Valchev After the holidays, i'd like to take a look at this with you. I remember we discussed these ridiculously long selectors, but i'm still having some issues getting them to work in the first place. Let's se if we can come up with something better. :-)

[I-Valchev]

Also as part of this, create fixtures for filelists and imagelists.

[bobdenotter]

In #889 I added that Imagelist and Filelist get populated in Fixtures.