Ticket #2857: add handling .zip extension.

Add 'shell/i/.zoo' to detect zip archive using .zip extension
in addition to 'type/i/^zip\ archive'.

Thanks ctmp1 <gvlatyshev@gmail.com> for the original patch.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
Merge branch '2857_zip'

* 2857_zip:
  Ticket #2857: add handling .zip extension.