Re: window-resizable confusion

[martin rudalics]

> I think the NOUP and NODOWN arguments should be replaced with a single
> argument, SUBTREE.  If the value is `upper-tree', that would be
> equivalent to NODOWN non-nil; if the value is `lower-tree', that would
> be equivalent to NOUP non-nil.

I'm not sure whether there are cases where I call this with both NOUP
and NODOWN non-nil, meaning don't check the argument window's sizes and
stay within the argument window's siblings.  So this would be a rather
hazardous change.

Instead I wrote a new function `window--resizable' which is a copy of
the old `window-resizable' and rewrote `window-resizable' such that it
doesn't have the NOUP and NODOWN arguments (which are only useful for
the internal workings of window resizing anyway).  It now doesn't have
the TRAIL/SIDE argument either which is only needed for implementing
`adjust-window-trailing-edge'.  Please have a look.

I still have to rename a number of window.el internal functions to use
the "window--" prefix.

martin