Sanitize frame geometry related functions

Sanitize frame geometry related functions

* src/nsfns.m (Fx_frame_geometry): Rename to Fns_frame_geometry.
(Fx_frame_edges): Rename to Fns_frame_edges.
* src/w32fns.c (Fx_frame_geometry): Rename to Fw32_frame_geometry.
(Fx_frame_edges): Rename to Fw32_frame_edges.
(Fx_mouse_absolute_pixel_position): Rename to
Fw32_mouse_absolute_pixel_position.
(Fx_set_mouse_absolute_pixel_position): Rename to
Fw32_set_mouse_absolute_pixel_position.
* lisp/frame.el (x-frame-geometry, w32-frame-geometry)
(ns-frame-geometry, x-frame-edges, w32-frame-edges)
(ns-frame-edges, w32-mouse-absolute-pixel-position)
(x-mouse-absolute-pixel-position)
(w32-set-mouse-absolute-pixel-position)
(x-set-mouse-absolute-pixel-position): Declare.
(frame-geometry, mouse-absolute-pixel-position)
(set-mouse-absolute-pixel-position): New functions.
(frame-edges): Rewrite in terms of x-/w32-/ns-frame-edges.