[MERGE] Add BTree based repository format flavours

[John Arbash Meinel]

John Arbash Meinel has voted resubmit.
Status is now: Resubmit
Comment:
Unfortunately, I'm pretty sure your diff isn't complete. It shows you 
modifying the definition of "development2" but not you *creating* 
development2, and dev2 doesn't exist yet in bzr.dev.

For details, see: 
http://bundlebuggy.aaronbentley.com/project/bzr/request/%3C1222381851.22491.1.camel%40lifeless-64%3E
Project: Bazaar