bzr 1.6

Finally, the long awaited bzr 1.6 has been released. This release includes new features like Stacked Branches, improved weave merge, and an updated server protocol (now on v3) which will allow for better cross version compatibility. With this release we have deprecated Knit format repositories, and recommend that users upgrade them, we will continue to support reading and writing them for the forseeable future, but we will not be tuning them for performance as pack repositories have proven to be better at scaling. This will also be the first release to bundle TortoiseBzr in the standalone Windows installer.