allow name and description settings in doUpdateGroup

You can set 'name' and 'description' separately in doCreateGroup, but the corresponding code in doUpdateGroup is not available. Using the settings interface for these parameters seems to work.  Also, the prompt for illegal attributes was incorrect. Should say 'gam update group...', not 'gam create group...'
'members' items key for members().list() GAPI call

The default 'items' key is not found when calling the members().list() GAPI, so no existing group members are returned from callGAPIpages. The correct key is 'members'.
Merge branch 'master' of https://github.com/ksdtech/GAM into ksdtech-master
git push origin masterMerge branch 'ksdtech-master'
Merge branch 'master' of github.com:jay0lee/GAM