c++: container leaks if exception thrown by handler.

An exception throw by a handler is re-thrown out of container.run() as expected, however
the container does not shut down cleanly and many leaks are reported by valgrind or asan. The container should be exception-safe.

To demonstrate the problem apply this small patch to the helloworld_direct example.

examples/cpp/helloworld_direct.cpp | 1 +

modified examples/cpp/helloworld_direct.cpp
@@ -53,6 +53,7 @@ class hello_world_direct : public proton::messaging_handler {

// Receive one message and stop listener
void on_message(proton::delivery &, proton::message &m) OVERRIDE

{ + throw std::runtime_error("thrown from on_message"); std::cout << m.body() << std::endl; listener.stop(); }