Changer the way the rows are handled during sort

I was having trouble with tablesort losing the custom classes of my TDs because it recreates a whole new body with new TRs when it sorts the table.

What i did:
- in bindTH(), i now send the whole TR in rowArr instead of an array with the content of the individual cells
- I removed newRow() and newBody(), and replaced them with applySort(), which detaches all the rows from the table, and replaces them in order.

Thus, all CSS/jQuery metadata is kept, including classes and event bindings.