Moved all of the capture_server socket setup code into the try block

Moved all of the capture_server socket setup code into the try block
so that the event gets set if a failure occurs during server setup
(otherwise the test will block forever).  Changed to let the OS assign
the server port number, and client side of test waits for port number
assignment before proceeding. The test data in DispatcherWithSendTests
is also sent in multiple send() calls instead of one to make sure this
works properly. [GSoC - Alan McIntyre]