Fixed memory leak of TabIface.

Added documentation of the XS interface on how the Ref<> and Clone<>
wrappers work.

xs/xsp/typemap.xspt

@@ -211,7 +211,6 @@
 %typemap{PresetHints*};
 %typemap{Ref<PresetHints>}{simple};
 %typemap{TabIface*};
-%typemap{Ref<TabIface>}{simple};
 
 %typemap{PrintRegionPtrs*};
 %typemap{PrintObjectPtrs*};