Remove the code related to "_result_ref" which was confusing and plain
wrong, as it generated something that compiled but crashed during
run-time due to the use of a pointer to an already destroyed stack
object.
Instead, correct the "out" typemap to create a new copy of the object,
which mostly works fine on its own, except that it depends on using
SwigValueWrapper if necessary, so add the call to cplus_value_type()
does this. This also required removing the code resolving typedefs in
the "type" attribute because it confused the base class logic and still
needs an explicit cast to the actual return type due to the use of (and
probable bug in) get_wrapper_func_return_type().
These changes mean that "cppouttype" typemap is not used any longer, so
remove it too.
A couple more tests pass now.
fd3e763656