[MERGE] (robertc) Add -Devil information on some Branch methods, plus comment and docstring corrections. (Robert Collins)

[Martin Pool]

Martin Pool has voted approve.
Status is now: Approved
Comment:
If we're marking a method as evil, maybe we should document somewhere 
what people are supposed to do instead?  Maybe not worth it, they can 
just ask here.

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C1191466339.31014.0.camel%40lifeless-64%3E