Fix: Individual column sorting was not distinct for multiple tables

- The `settings.aoPreSearchCols` array was being shared between every
  table on the table (test using a simple:
    $.fn.dataTableSettings[0].aoColumns ===
    $.fn.dataTableSettings[1].aoColumns
  ) which meant that a column filter aplpied to one table would be
  applied to all others.

- Fix is to deep copy the search model when adding a columns

- Fixes DataTables/DataTables issue #213

.datatables-commit-sync

@@ -1 +1 @@
-f799420905648a780426600e304c31cc82e1e56d
+bf16c47fd69b5d4460b5fa23d97ed1cb1060e4a3

media/js/jquery.dataTables.js

@@ -229,7 +229,7 @@
 		/* Add a column specific filter */
 		if ( oSettings.aoPreSearchCols[ iCol ] === undefined || oSettings.aoPreSearchCols[ iCol ] === null )
 		{
-			oSettings.aoPreSearchCols[ iCol ] = $.extend( {}, DataTable.models.oSearch );
+			oSettings.aoPreSearchCols[ iCol ] = $.extend( true, {}, DataTable.models.oSearch );
 		}
 		else
 		{