scilab: fix line number error in swigtesterror()
scilab: add pointer conversion builtin functions swig_this & swig_ptr
scilab: update null_pointer test ([] is no more null pointer use swig_ptr(0))
scilab: use swig_this to test pointers
scilab: fix typechecks
scilab: implement overloading_simple test
scilab: implement overload_complicated test