Major rewrite of display-buffer functions, atomic and side windows.

Major rewrite of display-buffer functions, atomic and side windows.

* buff-menu.el (Buffer-menu-switch-other-window): Use
display-buffer-same-frame-other-window.
(Buffer-menu-2-window): Use
pop-to-buffer-same-frame-other-window.

* progmodes/compile.el (compilation-start): Use
pop-up-window-set-height specifier.
(compilation-goto-locus): Rewrite window-setup code with new
display method specifiers.

* vc/ediff-mult.el (ediff-collect-custom-diffs)
(ediff-meta-show-patch): Use display-buffer-other-window.

* files.el (ctl-x-5-map): Remove binding for
display-buffer-other-frame.

* frame.el (pop-up-frame-alist, pop-up-frame-function)
(special-display-frame-alist): Update obsolescence declaration.

* mail/reporter.el (reporter-submit-bug-report): Adapt to new
display specifiers.

* man.el (Man-notify-when-ready): Use
display-buffer-other-window.

* pcomplete.el (pcomplete-show-completions): Use
display-buffer-other-window.

* ps-print.el (ps-line-lengths-internal, ps-nb-pages): Use
display-buffer-other-window.

* term.el (term-display-buffer-line): Call
display-buffer-other-window.

* window.el (window-child-count): New function.
(walk-window-tree-1, walk-window-tree, walk-window-subtree):
Move them here.
(windows-with-parameter, window-with-parameter)
(window-atom-root, make-window-atom, window-atom-check-1)
(window-atom-check): New functions.
(window-sides-vertical, window-sides-slots, window-sides-alist):
New options.
(window-side-check, window-check): New functions.
(composite-window-p, composite-root-window-p)
(composite-main-window-p, composite-support-window-p)
(composite-root-window, composite-major-window)
(composite-main-sibling, composite-lowest-child-role)
(compound-window-p, compound-main-window-p)
(compound-root-window, group-window-p, group-root-window): Remove,
their functionality is now provided by atomic and side windows.
(other-window): Check other-window-function parameter and rewrite
handling of no-other-window parameter.
(window-deletable-p, delete-window, delete-other-windows)
(split-window): Handle ignore-window-parameters, atomic and side
windows.  Call window-check.
(make-compound-window, make-window-group, make-support-window):
Remove, replaced by atomic and side windows.
(display-buffer-names, display-buffer-regexps): Remove, replaced
by display-buffer-alist.
(display-buffer-method-specifiers)
(display-buffer-macro-specifiers): New constants.
(display-buffer-default-specifiers): Rewrite.
(display-buffer-alist): New variable.
(display-buffer-other-window-specifiers)
(display-buffer-same-frame-specifiers)
(display-buffer-other-window-same-frame-specifiers)
(display-buffer-other-frame-specifiers): Rewrite with new
display specifiers.
(display-buffer-function, display-buffer-window)
(display-buffer-even-sizes, display-buffer-select-window, display-buffer-in-window):
Rewrite doc-string.
(display-buffer-set-height): Rename from display-buffer-adjust-height.
(display-buffer-set-width): Rename from display-buffer-adjust-width.
(display-buffer-in-window): Install no-other-window parameter if
required.
(display-buffer-reuse-window): New function.
(display-buffer-split-window-1, display-buffer-split-window):
Rewrite.
(display-buffer-split-atom-window, display-buffer-pop-up-window)
(display-buffer-pop-up-frame, display-buffer-pop-up-side-window):
New functions.
(display-buffer-normalize-specifiers-1)
(display-buffer-normalize-specifiers, display-buffer
(display-buffer-same-window, display-buffer-same-frame)
(display-buffer-other-window)
(display-buffer-same-frame-other-window, pop-to-buffer)
(pop-to-buffer-same-window, pop-to-buffer-same-frame)
(pop-to-buffer-other-window)
(pop-to-buffer-same-frame-other-window)
(pop-to-buffer-other-frame): Rewrite using new display
specifiers.
(special-display-regexps, special-display-function)
(same-window-buffer-names, same-window-regexps, pop-up-frames)
(display-buffer-reuse-frames, pop-up-windows)
(split-window-preferred-function, split-height-threshold)
(split-width-threshold, even-window-heights)
(display-buffer-mark-dedicated): Rewrite obsolete declarations.
(special-display-p, same-window-p): Rewrite with new display
specifiers.

* windows.texi (Windows): Rename sections "Frames and Windows"
to "Windows and Frames", "Compound Windows" to "Atomic Windows",
and "Window Groups" to "Side Windows".
(Splitting Windows, Deleting Windows): Rewrite sections dealing
with window parameters and ignore-window-parameters.  Describe
handling of atomic windows and side windows.
(Displaying Buffers): Describe method and other new display
specifiers, display-buffer-alist, and the new functions
display-buffer-reuse-window, display-buffer-pop-up-window,
display-buffer-pop-up-frame, and display-buffer-in-side-window.
Add description of specifier normalization
(Window Parameters): Describe functions windows-with-parameter
and window-with-parameter and the window parameters used by the
window handling routines.
(Composite Windows, Compound Windows, Window Groups): Sections
removed.
(Atomic Windows): New section on atomic windows.
(Side Windows): New section on side windows.