rename: make --after work if source is already in R state
I routinely want to use `hg addrem` and then fix up missed renames
manually using `hg mv -A`. This patch allows me to record such
renames from a source in state R to a target in state A.
Basic install:
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
See http://mercurial.selenic.com/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.