[BZ#638436] Add simpler push/pull keyboard shortcuts for two-pane merges
Submitted by Kai Willadsen
From Peter Tyser:
If there are only 2 panes, it might be nice to have Alt+and Alt+Shift+ to do the same thing. Eg if I'm in the left of 2 panes, it'd be nice to just press Alt+right to move a chunk to the right, and Alt+left to pull a chunk from the right. I work in 2-pane mode 98% of the time and I'm having issues remembering to hold shift in for pulls. I'm not a UI expert, so maybe changing the functionality of Alt+Shift+ based on 2/3 panes is a big no-no...