Fix category selector + add translations
Merge branch 'master' of https://github.com/CIRB/django-fixmystreet

Conflicts:
	django_fixmystreet/fixmystreet/forms.py
	django_fixmystreet/fixmystreet/locale/fr/LC_MESSAGES/django.mo
	django_fixmystreet/fixmystreet/locale/fr/LC_MESSAGES/django.po
	django_fixmystreet/fixmystreet/locale/nl/LC_MESSAGES/django.mo
	django_fixmystreet/fixmystreet/locale/nl/LC_MESSAGES/django.po