self destructing bell

if we don't have a bell element, the script cleans itself up; designs
that have a bell element that shouldn't be hidden will have to give it a
~nohide tag; in theory users wouldn't install bell if there is no such
element present, in practice users ask where the bell is after they
installed the script on their design that simply didn't feature the
element, this should clean up script load and confusion
self destructing label

if we don't have label prims, the script cleans itself up; mouse found a
clever solution to determine if we have label prims for this case;
unfortunate is that the label text on the default collar design is
slightly off center but that was always the case for any other collar
design that had labels smaller or greater than a dozen characters and
weren't using tortured cylinders; otherwhise the same as stated in #254