Emacs support: numerous changes. Most SCM commands now work in derived buffers (e.g. diff viewing buffers) as well as buffers backed by files. diff and log now work properly on repositories and files. Commit support is more solid. Doc strings are better.

#!/bin/sh

hg init
echo a > a
hg add a
hg commit -m "1" -d "0 0"
hg status
cp a b
hg copy a b
hg status
hg --debug commit -m "2" -d "0 0"
hg history
hg log a
md5sum .hg/data/b.d
hg cat b > bsum
md5sum bsum
hg cat a > asum
md5sum asum
hg verify