transitive copy/rename
Add support for transitive copy or rename operations, e.g.
hg rename a b
... (possibly edit b)
hg rename b c
hg commit ...
by actually renaming "b" as "c" while recording a copy of
"a" to "c" and a removal of "a".
#!/bin/sh
mkdir a
cd a
hg init
echo 123 > a
hg add a
hg commit -m "a" -u a -d "0 0"
cd ..
mkdir b
cd b
hg init
echo 321 > b
hg add b
hg commit -m "b" -u b -d "0 0"
hg pull ../a
hg heads