Update the daq parser to consume a port number as well as a broadcast interface name.

* This introduces a address:port parsing call into the net_writer code to allow it to handle both the port information as well.
* Removes a minor memory leak, by moving from strdup w/o a free to a std::string.
* As we no longer transmit data via daqd data concentrators this removes the DC code path from the net_writer broadcast section.
* Also removes to unneeded constants.