only recalculate favicon if it changes
only recalculate favicon if it changes

vector-im/vector-web,vector-im/vector-web,vector-im/vector-web,vector-im/vector-web,martindale/vector,vector-im/riot-web,vector-im/riot-web,vector-im/riot-web,vector-im/riot-web,vector-im/riot-web,vector-im/riot-web,martindale/vector,vector-im/vector-web