Roster window gets iconified instead of hidden when clicking on the tray icon
Bug description
When clicking on an IM client's systray icon, the expected behaviour is usually hiding the roster window; however, in Gajim, the roster window merely becomes iconified/minimized.
I don't know whether this is the way you want it to be or whether it's just something nobody cared about until now, but to me, it's quite annoying since I always hide IM clients by clicking on their tray icons.
It's in line 366 of statusicon.py in the latest hg repo version; win.iconify() should be replaced by win.hide(), quite obviously.
Steps to reproduce
Left-click on the systray icon when Gajim has the focus.
Software versions
OS version: Debian GNU/Linux
GTK version: 2.18.4
PyGTK version: 2.16.0