getLayersDrawingOrder is borked for SWIG 1.3.28 and greater

[hobu]

SWIG changed how it does getitem/setitem naming (maybe for the worse).  I sent a
message to the swig-devel list a couple of months ago, but didn't hear anything
back.  

I would prefer to not be using swig internals and actually have an intarray-like
entity, but here's a stopgap that will work for now.

        #if defined(SWIGPYTHON) && SWIG_VERSION >= 0x010329 /* 1.3.29 */
        intarray___setitem__(order, i, self->layerorder[i]);
        #else
        intarray_setitem(order, i, self->layerorder[i]);
        #endif