[FIX] tablesorter: change placement of processing formatting code to avoid triggering it when checkboxes are clicked. A redo of r52655 and r52656 (thanks Jonny - this should work in FF)

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/12.x@52660 b456876b-0849-0410-b77d-98878d47e9d5