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.
# repo.py - repository base classes for mercurial
#
# Copyright 2005 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.
class RepoError(Exception): pass