Undocumented options

[Lefty Leverenz]

While documenting Beeline command options in the Hive wiki, I found some options that aren't covered in the SQLLine doc:

   - showElapsedTime

   - maxHeight

   - timeout

   - trimScripts

   - allowMultiLineCommand

They are found in BeeLineOpts.java, and all but allowMultiLineCommand are in SqlLineOpts.java.

Should they be documented?  And if so, would someone please review Xuefu Zhang's preliminary descriptions in the comment on HIVE-6137?

Thanks.

-- Lefty Leverenz