Add border_width to window coordinates

[ortango]

In reference to #1968, this patch is to account to border_width for window coordinates when displaying on the currently focused window (-monitor -2).

Rather then add border width to the window's height and width, we are moving the x, y offsets. 100% of the window would be everything but the border. I looked through xlib manual and icccm, but did not come across a defacto standard for this.

[ortango]

This changes current behavior for both reparenting and non-reparenting wm's. In both cases 100% x/y offsets and height/width of the window fills the area inside the border/decorations.

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so these changes are a little to much. i tested the following wm's : bspwm, dwm, i3 and everything is fine with -m -{2,4}.
testing xmonad (after seeing the xmonad issue/commit) - both 2 and 4 are broken. did not realize that xmonad's ewmh support was optional. after enabling it this is working.

so, this patch also fixes -m -2 for other nonreparenting wm's aside from bspwm.

[DaveDavenport]

Thanks!