This changeset introduce an unbundler class to match the bundle2 bundler. It is
currently able to unbundle an empty bundle2 only and will gain more feature at
the same pace than the bundler.
It also comes with its special extension command in test.
This changeset is the very first of a long series. It create a new bundle2
module and add a simple class that generate and empty bundle2 container.
The module is documented with the current state of the implementation. For
information about the final goal you may want to consult the mercurial wiki
page:
http://mercurial.selenic.com/wiki/BundleFormat2
The documentation of the module will be updated with later patches adding more and
more feature to the format.
This patches also introduce a test case. This test case build and use its own
small extension that use the new bundle2 module. Since the new format is unable
to do anything right now, we could not use real mercurial code to test it.
Moreover, some advanced feature of the bundle2 spec will not be used by core
mercurial at all. So we need to have them tested.
