Improve DESC command for sets

When doing a Describe column family on a "table" with a "set" column, it doesn't show the type of the field in the set.
(I am just guessing it's probably also for map and list columns)

Also a small request(I can open another ticket if you prefer), it is possible to make the "Column family" keywords optional:
DESC[ribe] [Column Family] cf_name
So it will be possible like sql to just Desc table_name. (without typing much redundant expected text)