This patch catches the same kind of bad alias names caught by
Michael's patch.  There are some extensions:

1. Mutt makes sure that it doesn't _suggest_ bad names to the user.
2. If a name is bad, the user is informed, and may elect to fix the
   name.  In this case, mutt will automatically suggest a fixed
   version.
3. If the user insists in the bad name, it's written into the
   aliases file with proper quoting.
4. When mutt parses the aliases file, it now uses the normal
   tokenizer routines in order to properly handle quoted alias names.