tests/test-addremove

Enable path validation for copy, rename, debugwalk and other canonpath users.
This fixed the last bit of issue134.
Added some tests to test-rename and test-walk.

#!/bin/sh

hg init rep
cd rep
mkdir dir
touch foo dir/bar
hg -v addremove
hg -v commit -m "add 1" -d "1000000 0"
cd dir/
touch ../foo_2 bar_2
hg -v addremove
hg -v commit -m "add 2" -d "1000000 0"