Provide a way to get the automatically-selected port number

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I started with the code in SimpleReceive.cpp, and instead of specifying port 
7000, I changed the port specification to IpEndpointName::ANY_PORT, so that the 
system automatically chooses an available port.

However, I couldn't find a way to retrieve the actual port number assigned by 
the system.

The attached patch provides a UdpSocket::Port() method, which can be called 
after Bind() to retrieve the port.

Original issue reported on code.google.com by smokris on 4 Jan 2014 at 9:31

Attachments:

• udpsocket-get-port.patch