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.
adding dir/bar
adding foo
dir/bar
foo
adding dir/bar_2
adding foo_2
dir/bar_2
foo_2
adding a
adding c
adding b
adding d
removing a
removing c
recording removal of a as rename to b (100% similar)