Feature : destination collection

This adds a flag "-g" into the options to allow the user to pass a destination namespace in case they do not wish the target to have the exact same namespace as the source.  This is currently tested only for mongo-to-mongo connection.  If the -g flag is not specified then the destination namespace and the source namespace are identical.  If -g is specified then an equal number of target and destination namespaces must be specified or the connector will exit with an error.