Add check_url decorator, remove check_domain
Add check_url decorator, remove check_domain

check_domain was not used anywhere and was bugged (the domain argument
was ignored in favor of self.DOMAIN).
The check_url decorator checks if the URL can be handled, if not it will
return None. The idea is to avoid making unnecessary requests.

Boussadia/weboob,laurent-george/weboob,eirmag/weboob,laurent-george/weboob,RouxRC/weboob,willprice/weboob,Boussadia/weboob,yannrouillard/weboob,sputnick-dev/weboob,sputnick-dev/weboob,Konubinix/weboob,franek/weboob,Boussadia/weboob,laurent-george/weboob,eirmag/weboob,nojhan/weboob-devel,yannrouillard/weboob,Konubinix/weboob,nojhan/weboob-devel,frankrousseau/weboob,sputnick-dev/weboob,nojhan/weboob-devel,frankrousseau/weboob,RouxRC/weboob,franek/weboob,franek/weboob,eirmag/weboob,Konubinix/weboob,willprice/weboob,RouxRC/weboob,willprice/weboob,yannrouillard/weboob,frankrousseau/weboob,Boussadia/weboob