large speedup by storing sample table in class variable; _populate_supplier_name() becomes _populate_supplier_and_public_name() which is now called in populate() since it is no longer time consuming
trivial comment change, now that we get public name for sample as well
if public_name is passed in it is now set as the alias of the individual
also get individual.name and individual.alias, to allow for detecting changes in these
added detection for changes in individual name and alias, with the name test based on if use_supplier_name is in effect
added public_name as a property
fixed unecessary unwithdrawing