[MERGE] Nested trees: merge

[Ian Clatworthy]

Ian Clatworthy has voted comment.
Status is now: Semi-approved
Comment:
The code changes looks OK to me on the surface. My main concern with 
approving it is my lack of in-depth knowledge about the merge code so 
let me sit on it a few days.

I'd also like to better appreciate the end UI, given that do_merge() 
reports the # of conflicts *excluding* those in nested trees. IIUIC, the 
containing tree is merged, each nested tree is merged and reported on, 
then the containing tree is reported on? I wonder whether we need some 
summary or will that happen implicitly?

For details, see: 
http://bundlebuggy.aaronbentley.com/project/bzr/request/%3C49D64CE9.9010908%40aaronbentley.com%3E
Project: Bazaar