str.splitlines could not be used in 2d839579ce70, but _now_ we would like to
have lines with other line endings than \n.
Some fine occurences of (esc) markup of \r is replaced with multiple lines
ending with '\r (no-eol) (esc)'. That is no win but also no significant loss.
This change makes it possible to drop filtercr.py - _that_ is a win.
When diffing the following documents with --ignore-blank-lines (-B):
$ cat > a <<EOF
>
>
>
> b
> x
> d
> EOF
and:
$ cat > b <<EOF
> b
> y
> d
> EOF
the context lines are taken from the first document, even if the lines differ
(with -w or -b) or if the number of lines differ (with -B). In the second case,
we have to adjust the hunk new lines offsets or we end with inconsistent diffs
like (see the @@ offsets):
diff -r 0e66aa54f318 a
--- a/a
+++ b/a
@@ -1,4 +1,3 @@
b
-x
+y
d
Note that having different context lines in a and b means the diff can be
applied but is not invertible.
Reported by Nicholas Riley <com-selenic@sabi.net>