Make hg add foo; hg mv foo bar work. - foo will be removed (the user has a copy of its contents in bar) - bar will not be marked as a copy (there was no committed version of foo). We print a warning telling that to the user. Fixes issue269.

To run the tests, do:

cd tests/
python run-tests.py

See http://www.selenic.com/mercurial/wiki/index.cgi/WritingTests for
more information on writing tests.