archive: delay extraction of file revisions
This allows us to look only at the filelogs we're interested in,
providing a nice speedup if we're archiving only part of a repository.
Basic install:
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
See http://www.selenic.com/mercurial/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.