Bottom stack tiling: tweak position of newly added window

[mixu]

Right now, when you use bottom stack tiling and add a new window:

[       1       ]
[   2   ] [  3  ]

becomes

[      New      ]
[ 1 ] [ 2 ] [ 3 ]

Would be nicer if the result would be

[       1       ]
[ 2 ] [ 3 ] [ N ]

since I usually put a terminal window on top and want it to stay there.

[ashnur]

When I open a new skype chat window, it not only does this, but it also switches the screen, showing the new window(which follows the above-described stacking of the starting screen) over the windows of the screen it switched on.