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".
%% should show b unknown
? b
%% should show b unknown and c modified
M c
? b
%% should show b added and c modified
M c
A b
%% should show a removed, b added and c modified
M c
A b
R a
%% should show b added and c modified
M c
A b
%% should show b unknown and c modified
M c
? b
%% should show b unknown
? b
%% should show a b and c
a
b
c