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.

1 files updated, 0 files merged, 0 files removed, 0 files unresolved
removing b
abort: update spans branches, use 'hg merge' or 'hg update -C' to lose changes