Returns the release version of the software.
The cgversion command is invoked as either one of :
CG> cgversion CarthaGene version 0.999-LKH, Copyright (c) 1997-2004 (INRA). CarthaGene comes with ABSOLUTELY NO WARRANTY. CarthaGene is free software. You are welcome to redistribute it, under certain conditions. See the License file for information. Type 'help' for help. CG>