"Open externally" warrants a shortcut

Submitted by Massimo B.

Description

I often need meld to diff folder trees of snapshotted subvolumes trees with the current subvolume, there I deal with many different types like JPG, PDF or other media files. Most often I need "Open externally", currently only available from context menu or double click.

Please add a shortcut editor to use most of the already existing functions via shortcut.

OT: Some day I would like to have some preview at least for pictures, not sure if that is beyond the scope of meld.

Edited Dec 14, 2018 by Kai Willadsen