Fix: Extending objects in the API could cause scope errors over multiple tables

- See thread 20075 for the original report

- Basically the issue here was that the object being used for the API
  extension on objects (e.g. `table.ajax` is an object) the object was
  not unique to each API instance, so it was being shared between
  instances and as a result, whatever instance was created last, would
  win!

- Fix is to use a new object each time.

.datatables-commit-sync

@@ -1 +1 @@
-824641df1d8396a88c495ed258915287046c1c55
+caffdb49eec87db2e3c1999eaec6736257b8f6b5

media/js/jquery.dataTables.js

@@ -6756,6 +6756,8 @@
 			// Value
 			obj[ struct.name ] = typeof struct.val === 'function' ?
 				methodScoping( struct.val, struct ) :
+				$.isPlainObject( struct.val ) ?
+					{} :
 					struct.val;
 	
 			obj[ struct.name ].__dt_wrapper = true;