Directly use self.flavor
Make image optional and add rudimentary support for block devices

The image keyword is now optional and defaults to None. The
block_devices keyword will map to the block_device_mapping_v2 in
novaclient. Some simple parsing will happen to allow a higher level use
than what --block-device presents in the shell.
Refactor _getImage to allow any image callable to be used

This may eventually be extended to work with block devices.
Add block devices to kwargs for servers.create
Combine all test auth data into one dict

Combined all of the test auth keywords into a dict to make setting up a
buildslave slightly less tedious.
Simplify more redundant test args

Most creations of the slave now can use the shorter **self.bs_args.
Test OpenStackBuildSlave.stop_instance
Test basic block_devices functionality
Add a kwargs to OpenStackBuildSlave

Add a kwargs to allow people that know what needs to be passed to
servers.boot the option to do so.
Add release notes and documentation
Fix release notes

I missed a blank line.
re-structure cfg-buildslaves manual page

* put documentation for supported latent buildslaves into separate
  documents
* polish a bit each page to give an overview of what they provide

Fixes ticket:2861
Merge sa2ajj/buildbot:bugfix-2861 (PR #1232)
Remove the "lone pipe" exception in ShellCommand argument handling

As discussed in
<http://news.gmane.org/find-root.php?group=gmane.comp.python.buildbot.devel&article=10518>.
This makes it possible to pass a pipe as an argument, plus it makes argument
handling consistent between Windows and Unix-likes.
Stop using BuildStepStatus when running steps
Update status string handling for most tests

There are still some failing tests due to a lingering issue around
BuildStep no longer supporting a `describe` method.
add more compatibility for old-style steps

* BuildStep implements describe()
* Factor out command_to_string
Fix ShellSequence status strings; do error reporting in twistd.log
fix remaining tests
Remove the BuildSetStatus class, still allowing unpickling