grep: display correct user/revision for --all in reverse. Also handle multiple occurrences of the same line by storing linestates in an array instead of a dict, and using difflib to compute the difference between linestates.

#!/bin/sh

unset HGUSER
EMAIL="My Name <myname@example.com>"
export EMAIL

hg init test
cd test
touch asdf
hg add asdf
hg commit -d '1000000 0' -m commit-1
hg tip