diffstat: scale adds/removes proportionally to graph width
The previous method of scaling had a tendency to include graph lines that
went past the output width when the file with the most changes had a very
large number of changes.
#!/bin/sh
echo "[extensions]" >> $HGRCPATH
echo "hgk=" >> $HGRCPATH
hg init repo
cd repo
echo a > a
hg ci -Am adda
hg debug-cat-file commit 0