Minor update: Added support for data-weight="".

I added the option 'weightselector' which allows the selector of either 'data-weight="'' or 'rel=""'.
The if statement that replaces '$(this).attr("rel")':
'((opts.weightselector == "rel") && $( this ).attr('rel') ||
(opts.weightselector == "data") && $( this ).data('weight'))'