Add an Emacs interface in contrib.

Add an Emacs interface in contrib.

This is an Emacs interface for git. The user interface is modeled on
pcl-cvs. It has been developed on Emacs 21 and will probably need some
tweaking to work on XEmacs.

The basic command is 'M-x git-status' which displays a buffer listing
modified files in the selected project tree. In that buffer the
following features are supported:

  - add/remove files
  - list unknown files
  - commit marked files
  - manage .gitignore
  - commit merges based on MERGE_HEAD
  - revert files to the HEAD version
  - resolve conflicts with smerge or ediff
  - diff files against HEAD/base/mine/other or combined diff
  - get a log of the revisions for specified files

There are plenty of unimplemented features too, see the TODO list at
the top of the file...

Signed-off-by: Alexandre Julliard <julliard@winehq.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>