Update referers.yml

Voila.fr changes its parameter to kw
Merge branch 'patch-1' of github.com:glefait-dbi/referer-parser into glefait-dbi-patch-1
Merge branch 'glefait-dbi-patch-1'
Updated ./resources/referers.yml, referers.json and ./resources/referer-tests.json in sub-folder following update(s) to master copy