(Display): Add 'Fringe Bitmaps' and 'Pointer

(Display): Add 'Fringe Bitmaps' and 'Pointer
Shapes' to menu.
(Standard Faces): Doc fix for fringe face.
(Fringes): Add `overflow-newline-into-fringe' and
'indicate-buffer-boundaries'.
(Fringe Bitmaps, Pointer Shapes): New nodes.
(Display Property): Add 'Pixel Specification' and 'Display Fringe
Bitmaps' to menu.
(Specified Space): Describe pixel width and height.
(Pixel Specification): New node.
(Other Display Specs): Add `slice' property.
(Display Fringe Bitmaps): New node.
(Images): Add 'Image Slices' to menu.
(Image Descriptors): Add `:pointer' and `:map' properties.
(Showing Images): Add slice arg to `insert-image'.  Add
'insert-sliced-image'.