* Support Pyrex 0.9.9, required changing how we handle exceptions in Pyrex. (John Arbash Meinel, #582656)
* ``bzr clean-tree`` should not delete nested bzrdirs. Required for proper support of bzr-externals and scmproj plugins. (Alexander Belchenko, bug #572098)
* Reduce peak memory by one copy of compressed text. (John Arbash Meinel, #566940)
* Support Pyrex 0.9.9, required changing how we handle exceptions in Pyrex. (John Arbash Meinel, #582656)