Use of NO-NOSELECT in mail_location

[Joseph Tam]

I enabled NO-NOSELECT in mail_location as it seemed to be an
optimization without negative consequences.  The wiki states

 	NO-NOSELECT : Automatically delete any \NoSelect mailboxes that
 	have no children. These mailboxes are sometimes confusing to
 	users. Also if a \NoSelect mailbox is attempted to be created with
 	"CREATE box/", it's created as selectable mailbox instead.

The last sentence is important: if you allow this, you won't be able to
create folders (i.e. directories); this caught me offguard.  If you use
mbox, this is something you don't want to enable.

Joseph Tam <jtam.home at gmail.com>