Extended zjturner's changes to encompass all function dispatch and use PyErr_WriteUnraisable to handle exceptions during __del__.

Also added test cases for the unnamed temporary destruction that is throwing assertions in Python 3.5.

Examples/test-suite/python_destructor_exception.i

@@ -0,0 +1,17 @@
+/* File : example.i */
+%module python_destructor_exception
+%include exception.i
+
+%exception ClassWithThrowingDestructor::~ClassWithThrowingDestructor()
+{
+  $action
+  SWIG_exception(SWIG_RuntimeError, "I am the ClassWithThrowingDestructor dtor doing bad things");
+}
+
+%inline %{
+class ClassWithThrowingDestructor
+{
+};
+
+%}
+