[MERGE] Only sign 8-bit strings

[John Arbash Meinel]

Aaron Bentley wrote:
> Aaron Bentley has voted +1 (conditional).
> Status is now: Conditionally approved
> Comment:
> Error message has a comma splice.  It should be "You can't sign Unicode
> text; it must be encoded first." or "You can't sign Unicode text.  It
> must be encoded first."
> 
> Otherwise, seems reasonable.
> 

That is actually just the doc string for the test case. But I'll fix it
anyway. Thanks,

John
=:->