merge: remember rename copies and parents properly on commit
record copies in dirstate even if rename was remote
this lets us record it properly at commit
teach checkfilemerge about copies, including merge cases
pull old copy code out of commit
extend rename-merge1 test to show file index
adding a
diff -r 107ba6f817b5 -r 310ce7989cdc a
--- a/a Thu Jan 01 00:00:01 1970 +0000
+++ b/a Thu Jan 01 00:00:02 1970 +0000
@@ -1,2 +1,3 @@ confuse str.splitlines
confuse str.splitlines
embedded
newline
+clean diff