gs-server extra option to control port
Currently gs2-server tests port numbers to see if it is already in use. If it is, then it increases the port number used until it finds one that is free. This can be undesirable a certain times. Add an option that controls whether or not it can auto change the port.
What Greenstone 3 does is not known at the time of writing, however in implementing this new option it should also work for Greenstone 3.