* python/dbus_bindings.pyx (MessageIter::append_strict): check for

* python/dbus_bindings.pyx (MessageIter::append_strict): check for
  STRUCT_BEGIN not TYPE_STRUCT in indicate we are marshalling a struct

* python/service.py (Object::_message_cb): handle exceptions correctly
  by sending them over the wire to the calling app.  This makes sure
  the client returns immediately instead of waiting the 15 seconds to
  timeout.

* test/python/test-client.py (TestDBusBindings::testBenchmarkIntrospect):
  Add a test to benchmark how long it takes to introspect a service and
  call a method which returns a large element (pretty fast)

* test/python/test-service.py (TestObject::GetComplexArray): new test
  method which pushes a lot of data