Describe frame geometry and related functions in Elisp manual

Describe frame geometry and related functions in Elisp manual

* doc/lispref/display.texi (Size of Displayed Text, Line Height)
(Showing Images): Update references.
* doc/lispref/elisp.texi (Top): Update node listing.
* doc/lispref/frames.texi (Frame Geometry): New node.  Move
`Size and Position' section here.
(Size Parameters): Update references.
(Mouse Position): Update references and nomenclature.  Describe
new functions `x-mouse-absolute-pixel-position' and
`x-set-mouse-absolute-pixel-position'.
* doc/lispref/windows.texi (Window Sizes): Update references.
(Resizing Windows): Update references.  Move description of
`fit-frame-to-buffer' here.
(Coordinates and Windows): Update nomenclature and references.
Describe new arguments of `window-edges'.  Comment out
descriptions of `window-left-column', `window-top-line',
`window-pixel-left' and `window-pixel-top'.  Describe
`window-absolute-pixel-position'.