copy: simplify inner copy
- save dirstate lookup and exists check
- do all fs work inside a single dryrun clause
- move unlinking into inner copy section
- move target dir creation
- eliminate undelete mess
- fix a bug on mv a -> b -> a after merge
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.