[BZ#761642] places-menu: Enable to unmount places

Submitted by Rémy Lefevre

Link to original bug (#761642)

Description

Created attachment 320553 Screenshot

Until now, it was unfortunately not possible to unmount removable devices or network shares from the places-menu.

This patch enable to unmount removable devices and network shares from the places menu by checking for each menu entry if the entry is removable. If yes, an eject button is placed next to the entry label and bind to an eject procedure.

Can you please review this patch and and if OK push it to the master branch?

Thanks!

Attachment 320553, "Screenshot":