Blender Git Loki

I hesitate to call it a bugfix... but it's a removal of a very ancient
(2001) hack that enforced opening renderwindows smaller than screen size.

The notes I could find referred to testing old 3d cards, which failed to
give graphics memory for large windows. Another note was an issue on OSX,
where the topbar and windowbar gets hidden otherwise.
That latter case I corrected now.

Will organize good testing for this, if there's issues, will uncommit :)