Cleaning up test client

Karma was overkill, and was removed from the test client argument
generation. Default argument values were also removed, all are now
required.
Port number is now configurable, and mandatory, for the server
Test client now checks packet from server.

The test client ensures that the transmit timestamp is after the receive
timestamp, that the fixed originate value is correct, and that the mode
is server. Some refactoring was done with the packet.cpp test to combine
utilities.