interhg: allow more flexible pattern specification (fixes 2/3 of issue699) - something else than "pat" followed by a number can be used as key - something else than "/" can be used as delimiter - "ilmsux" flags (e.g. "i" for case insensitive) can be used

#!/bin/sh
#
mkdir t
cd t
hg init
echo 0 > a
echo 0 > b
hg ci -A -m m -d "1000000 0"
hg rm a
hg cat a
sleep 1 # make sure mtime is changed
echo 1 > b
hg ci -m m -d "1000000 0"
echo 2 > b
hg cat -r 0 a
hg cat -r 0 b
hg cat -r 1 a
hg cat -r 1 b