basemixer: Add pad templates
basemixer: Add pad templates

Change-Id: I5447fbcff64a9c1f50a6a01ad12e3bd06e84d2d5

TribeMedia/kms-elements,Kurento/kms-elements,TribeMedia/kms-elements,shelsonjava/kms-elements,shelsonjava/kms-elements,Kurento/kms-elements,Kurento/kms-elements,TribeMedia/kms-elements,shelsonjava/kms-elements