Fix for bug 80289: Group restrictions are now identified with checkboxes instead...

Fix for bug 80289: Group restrictions are now identified with checkboxes instead of select widgets.  Also, product groups are now only offered if they are either already set, or match the current product (i.e. the option to set a product bit for a product other than the one the bug is in is no longer available) This results in much less clutter for the admin folks on sites with lots of products.
Patch by Joe Robbins <jmrobins@tgix.com>
r= justdave@syndicomm.com