[FIX] tablesorter: only apply previous commit (r53197) when ajax is used to avoid issues with undimming rows when process is complete

git-svn-id: file:///var/local/code.tiki.org/tikisvn/trunk@53198 b456876b-0849-0410-b77d-98878d47e9d5
[REF] tablesorter: change logic for setting whether column indexes or selectors are used and move settings into abstract classes (indexes used for plugins and selectors used for standard tiki tables)

git-svn-id: file:///var/local/code.tiki.org/tikisvn/trunk@53199 b456876b-0849-0410-b77d-98878d47e9d5