keyword: support copy and rename
copy/rename destinations being unversioned and possibly ignored by
the extension should not contain expanded keywords.
Files copied/renamed from an ignored source are not touched.
Add tests covering both of the above cases, plus the corner case of
cp symlink foo; hg cp -A symlink foo (where foo becomes a regular file).
$ hg init
$ touch unknown
$ touch a
$ hg add a
$ hg ci -m "1"
$ touch b
$ hg add b
$ hg ci -m "2"
Should show unknown
$ hg status
? unknown
$ hg revert -r 0 --all
removing b
Should show unknown and b removed
$ hg status
R b
? unknown
Should show a and unknown
$ ls
a
unknown