Cogito: cg-tag creates a tag object only if -s is specified

cg-tag only creates a tag object if -s (sign) is specified.  This not 
only doesn't work properly with a fair number of tools (e.g. gitk), but 
it also means that any description the user has entered via the -d 
option is silently discarded!

Please create a tag object for all tags, even if it is not signed.

	-hpa