* emulation/cua-base.el (cua-use-hyper-key): Replaced by ...

* emulation/cua-base.el (cua-use-hyper-key): Replaced by ...
(cua-rectangle-modifier-key): ... this.	 New defcustom.	 Can now
select either meta, hyper, or super modifier for rectangle commands.
(cua--rectangle-modifier-key): New defvar.
(cua--M/H-key): Use it.	 Remove special case for 'space.
(cua--init-keymaps): Initialize it from cua-rectangle-modifier-key
on X, to meta otherwise.  Always bind C-return to toggle
rectangle.  Pass ?\s instead of 'space to cua--M/H-key.

* emulation/cua-rect.el (cua-help-for-rectangle): Use
cua--rectangle-modifier-key.  Handle super modifier too.
(cua--init-rectangles): Always bind C-return to toggle rectangle.
Pass ?\s instead of 'space to cua--M/H-key and cua--rect-M/H-key.