diff: --ignore-cr-at-eol

A new option --ignore-cr-at-eol tells the diff machinery to treat a
carriage-return at the end of a (complete) line as if it does not
exist.

Just like other "--ignore-*" options to ignore various kinds of
whitespace differences, this will help reviewing the real changes
you made without getting distracted by spurious CRLF<->LF conversion
made by your editor program.

Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
[jch: squashed in command line completion by Dscho]
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/completion/git-completion.bash

@@ -1399,7 +1399,7 @@ __git_diff_common_options="--stat --numstat --shortstat --summary
 			--patch-with-stat --name-only --name-status --color
 			--no-color --color-words --no-renames --check
 			--full-index --binary --abbrev --diff-filter=
-			--find-copies-harder
+			--find-copies-harder --ignore-cr-at-eol
 			--text --ignore-space-at-eol --ignore-space-change
 			--ignore-all-space --ignore-blank-lines --exit-code
 			--quiet --ext-diff --no-ext-diff