* term/ns-win.el: Rename ns- functions/variables to the

* term/ns-win.el: Rename ns- functions/variables to the
corresponding x- versions.
(x-select-text, x-cut-buffer-or-selection-value)
(x-disown-selection-internal, x-get-selection-internal)
(x-own-selection-internal, x-defined-colors, xw-defined-colors)
(x-display-mm-width, x-display-mm-height)
(x-display-backing-store, x-display-save-under)
(x-display-visual-class, x-display-screens, x-focus-frame): Remove
defaliases.

* image.c:
* nsfns.m:
* nsselect.m:
* nsterm.h:
* nsterm.m: Rename ns prefixed functions/variables to the
corresponding x versions.  Update references.