[MERGE] Review feedback.

[John Arbash Meinel]

John Arbash Meinel has voted approve.
Status is now: Approved
Comment:
I should mention that:
+    def _create_merged_file(self):

Would be a great use of the new BranchBuilder updates I put together. 
However, the patch as a whole looks good. Let's get it for 1.7

For details, see: 
http://bundlebuggy.aaronbentley.com/project/bzr/request/%3C1220318923.19324.26.camel%40lifeless-64%3E
Project: Bazaar