(ansi-color-process-output): Use markers instead

(ansi-color-process-output): Use markers instead
of positions for start and end of region.
(ansi-color-apply-on-region): Rewrote code to make it more robust.
Previously, occasional mistakes happend when fontifying many
chunks of output (eg. ls --color=yes /dev).  This happened
whenever an overlay was created up to the end of the region, which
coincided with the process-mark.  New text would then be added
within that overlay instead of after it.
(ansi-color-make-extent): Overlays are created with the property
`modification-hooks' set to '(ansi-color-freeze-overlay).
(ansi-color-freeze-overlay): New function.  When inserting text at
the end of the overlay, the overlay will resize.

(ansi-color-process-output): Doc change.
(ansi-color-unfontify-region): Doc change.  No longer installed
automatically in font-lock-unfontify-region-function.
(ansi-color-apply): Doc change.
(ansi-color-apply-on-region): Use extents or overlays instead of
text-properties.
(ansi-color-make-extent): New function.
(ansi-color-set-extent-face): New function.

(ansi-color-process): Removed, Emacs and XEmacs
both use ansi-color-process-output, now.
(ansi-color-process-output): Doesn't return string anymore.  It is
installed in comint-output-filter-functions for both Emacs and
XEmacs, now.
(ansi-color-unfontify-region): Simplified code removing variables
pos and start-ansi.
(ansi-color-apply): Put text-property ansi-color before putting
text-property face because ansi-color-unfontify-region is called
immediately after the call to put-text-property.
(ansi-color-context-region): Doc change.
(ansi-color-filter-region): Simplified code.
(ansi-color-apply-on-region): Changed start to start-marker, using
a marker explicitly.  Put text-property ansi-color before putting
text-property face because ansi-color-unfontify-region is called
immediately after the call to put-text-property.

(ansi-color-faces-vector): Doc change.
(ansi-color-for-comint-mode): Changed :type property to choice.
(ansi-color-last-context): Removed.
(ansi-color-process-output): Don't use ansi-color-last-context, as
the main functions will store their context now.
(ansi-color-context): Doc change.
(ansi-color-filter-apply): Rewrote it based on ansi-color-apply.
Uses ansi-color-context such that repeated calls will strip
partial escape sequences, too.
(ansi-color-apply): Simplified code.  Colorize end of string if
face is not null.  Store context in new (FACE STRING) format, such
that repeated calls will strip partial escape sequences, too.
Append faces to face property using ansi-color-apply-sequence such
that cumulative mode actually works.
(ansi-color-context-region): New variable.
(ansi-color-filter-region): Rewrote it based on
ansi-color-apply-on-region.  Uses ansi-color-context-region such
that repeated calls will strip partial escape sequences, too.
(ansi-color-apply-on-region): Simplified code.  Colorize end of
region if face is not null.  Store context in new (FACE POS)
format, such that repeated calls will strip partial escape
sequences, too.  Append faces to face property using
ansi-color-apply-sequence such that cumulative mode actually
works.
(ansi-color-apply-sequence): New function.
(ansi-color-get-face): When the default face is added to the list
of faces, all previous settings are discarded and the list of
faces is set to '(default).

(ansi-color-faces-vector): Use nil for the default
face, such that ansi-color-apply and ansi-color-apply-on-region
will do the right thing.
(ansi-color-apply): Do the right thing, ie. if ansi-color-get-face
returns nil, set the list of faces back to nil instead of
appending the result of ansi-color-get-face to the front of the
list.

(ansi-color-for-comint-mode): Doc change.
(ansi-color-process): Doc change.
(ansi-color-last-context): New buffer-local variable.
(ansi-color-process-output): New function.  It is automatically
added to comint-output-filter-functions if this is XEmacs.
(ansi-color-unfontify-region): New optional parameter for XEmacs
compatibility.  Check wether font-lock-syntactic-keywords is
boundp before removing the syntax table text property, as XEmacs
doesn't have it.
(ansi-color-filter-region): Doc change.
(ansi-color-apply-on-region): Doc change.
(ansi-color-make-face): New function.  Compatibility layer for
XEmacs.  Return temporary faces instead of cons cells for XEmacs.
(ansi-color-make-color-map): Use ansi-color-make-face.
(ansi-color-get-face): Avoid face text property '(nil) as results
in an errow for XEmacs.

(ansi-color-unfontify-region): New function.  Uses
text-property ansi-color in order to preserve fontification by
ansi-color.  When the package is loaded, a lambda expression is
put onto font-lock-mode-hook.  This lambda expression will check
font-lock-unfontify-region-function and replace
font-lock-default-unfontify-region with
ansi-color-unfontify-region.
(ansi-color-apply): Add text-property ansi-color in addition to
text-property face.
(ansi-color-apply-on-region): Add text-property ansi-color in
addition to text-property face.
(save-buffer-state): Copy of the macro that is also used by
lazy-lock and font-lock.

(ansi-color-for-comint-mode): New option.
(ansi-color-for-comint-mode-on): Set ansi-color-for-comint-mode.
(ansi-color-for-comint-mode-off): Ditto.
(ansi-color-for-comint-mode-filter): Ditto.
(ansi-color-process): New function.  Uses
ansi-color-for-comint-mode to decide what to do.  This function is
added to comint-preoutput-filter-functions when the package is
loaded.

(ansi-color-for-shell-mode-set): Removed.
(ansi-color-for-shell-mode): Removed.

(ansi-color-for-shell-mode-set): New function with
the lambda expression from the ansi-color-for-shell-mode :set
property.  Additionally, modify shell-mode-hook to enable or
disable font-lock-mode for future shell buffers.
(ansi-color-for-shell-mode): The :set property calls
ansi-color-for-shell-mode-set instead of a lambda expression.

(ansi-color-for-shell-mode): Doc change.
(ansi-color-context): New variable.
(ansi-color-apply): Save context between calls.