Add a link to open an already attached attachment

[rcubetrac]

Reported by tsarboni on 10 Dec 2012 17:07 UTC as Trac ticket #1488860

Hi,
It can be usefull to be able to open an already attached attachment by clicking on its name to view if it's really the document we want to send.
Most of other webmails have this functionnality.
Thank you by advance.

Keywords: Attachment
Migrated-From: http://trac.roundcube.net/ticket/1488860