[openbox] Support resolution-independent relative sizes in move/resize action

[Kai Großjohann]

Jochen Schweizer wrote:
> With a little bit help from others I wrote 2 scripts (one for
> selecting and one for sending/sqeezing applications to areas). Both
> scripts use a modified version of wmctrl and one configurationfile.
If I understand the source correctly, then this still does not support
resolution-independent settings.

That is, I can say I want a window N pixels wide, but I can't say I want
a window 1/2 of the screen width and have it work on different screens.

Of course, I can do "wmctrl -d" and munge the output...  Yeah, that
might be workable.  But still, OpenBox natively provides a method to
resize windows, it just does not support the width/height computation.

Kai