bug#22785: 24.5; comint/shell modes should be merged with term mode

[Per Bothner <per@bothner.com>]

The "line" submode of term mode duplicates much of the functionality
of comint mode.  When I wrote term mode, my hope was that it would
subsume comint mode, or that comint mode would be built on top of
term mode.  That never happened - so far.

'shell mode' should basically be the same as 'term' mode, except
that shell mode starts of in line-editing mode, while term mode
starts up in character mode.

There are obvious advantages to merging these modes. One is
we have ansi escape sequence handling in a single place.
Another is that you can run console applications from shell mode.

In GNU Emacs 24.5.1 (x86_64-redhat-linux-gnu, GTK+ Version 3.18.7)
  of 2016-02-02 on buildhw-05.phx2.fedoraproject.org
Windowing system distributor `Fedora Project', version 11.0.11800000
System Description:	Fedora release 23 (Twenty Three)

Configured using:
  `configure --build=x86_64-redhat-linux-gnu
  --host=x86_64-redhat-linux-gnu --program-prefix=
  --disable-dependency-tracking --prefix=/usr --exec-prefix=/usr
  --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc
  --datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib64
  --libexecdir=/usr/libexec --localstatedir=/var
  --sharedstatedir=/var/lib --mandir=/usr/share/man
  --infodir=/usr/share/info --with-dbus --with-gif --with-jpeg --with-png
  --with-rsvg --with-tiff --with-xft --with-xpm --with-x-toolkit=gtk3
  --with-gpm=no build_alias=x86_64-redhat-linux-gnu
  host_alias=x86_64-redhat-linux-gnu 'CFLAGS=-DMAIL_USE_LOCKF -O2 -g
  -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2
  -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4
  -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
  -m64 -mtune=generic' LDFLAGS=-Wl,-z,relro'

Important settings:
   value of $LANG: en_US.UTF-8
   value of $XMODIFIERS: @im=ibus
   locale-coding-system: utf-8-unix

Major mode: Shell-script

Minor modes in effect:
   sh-electric-here-document-mode: t
   diff-auto-refine-mode: t
   xterm-mouse-mode: t
   tooltip-mode: t
   electric-indent-mode: t
   mouse-wheel-mode: t
   tool-bar-mode: t
   menu-bar-mode: t
   file-name-shadow-mode: t
   global-font-lock-mode: t
   font-lock-mode: t
   auto-composition-mode: t
   auto-encryption-mode: t
   auto-compression-mode: t
   line-number-mode: t
   transient-mark-mode: (only . t)

Recent messages:
Wrote /home/bothner/DomTerm/bin/domterm
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Saving file /home/bothner/DomTerm/bin/domterm...
Wrote /home/bothner/DomTerm/bin/domterm
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Saving file /home/bothner/DomTerm/bin/domterm...
Wrote /home/bothner/DomTerm/bin/domterm
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Saving file /home/bothner/DomTerm/bin/domterm...
Wrote /home/bothner/DomTerm/bin/domterm

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message idna format-spec
rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils info css-mode ispell view mule-util
parse-time sgml-mode sh-script smie executable etags ring texinfo
smerge-mode diff-mode easy-mmode scheme nxml-uchnm rng-xsd xsd-regexp
rng-cmpct rng-nxml rng-valid rng-loc rng-uri rng-parse nxml-parse
rng-match rng-dt rng-util rng-pttrn nxml-ns nxml-mode nxml-outln
nxml-rap nxml-util nxml-glyph nxml-enc xmltok add-log conf-mode
help-mode autoconf autoconf-mode make-mode vc-dispatcher vc-svn cc-langs
misearch multi-isearch vc-git js advice help-fns byte-opt bytecomp
byte-compile cl-extra cl-loaddefs cl-lib cconv json imenu thingatpt
cc-mode cc-fonts easymenu cc-guess cc-menus cc-cmds cc-styles cc-align
cc-engine cc-vars cc-defs vc-cvs server time-date xt-mouse tooltip
electric uniquify ediff-hook vc-hooks lisp-float-type mwheel x-win x-dnd
tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment
lisp-mode prog-mode register page menu-bar rfn-eshadow timer select
scroll-bar mouse jit-lock font-lock syntax facemenu font-core frame cham
georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese hebrew greek romanian slovak czech european ethiopic
indian cyrillic chinese case-table epa-hook jka-cmpr-hook help simple
abbrev minibuffer nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote make-network-process
dbusbind gfilenotify dynamic-setting system-font-setting
font-render-setting move-toolbar gtk x-toolkit x multi-tty emacs)

Memory information:
((conses 16 515998 51413)
  (symbols 48 29080 0)
  (miscs 40 1048 8712)
  (strings 32 53861 12727)
  (string-bytes 1 1792324)
  (vectors 16 27981)
  (vector-slots 8 1509840 153066)
  (floats 8 176 561)
  (intervals 56 77667 486)
  (buffers 960 103)
  (heap 1024 74981 4504))

-- 
	--Per Bothner
per@bothner.com   http://per.bothner.com/

-- 
	--Per Bothner
per@bothner.com   http://per.bothner.com/