P4: Use config.error, instead of collecting errors by hand.
P4: Use tools provided by CompositeStepMixin.
Reason: allow 'reason' to be overriden in Schedulers and show in Builder page
Reason: update docs and release notes
Docs: update some index references
repo codingStyle fixes

- repo step and unit tests are now pep8 compliant
- fixed camelCase for repo step parameters
- removed usage of properties as input of the step.
  Its now job of use to choose which property name he wants via renderable
- added test on repo download from changesource
- update doc and release notes

Signed-off-by: Pierre Tardy <pierre.tardy@intel.com>
repo: add RepoDownloadsFromChangeSource renderable

Suggestion from Tom to put this away from the step code.
In cunjunction with FlattenList, this works well.

+ some more minor review handling

Signed-off-by: Pierre Tardy <pierre.tardy@intel.com>
Update release notes.
Merge branch 'repo-coding-style' into buildbot-0.8.8.

- repo step and unit tests are now pep8 compliant
- fixed camelCase for repo step parameters
- removed usage of properties as input of the step. Its now job of use to choose which property name he wants via renderable
- added test on repo download from changesource
- update doc and release notes
Revert adding slave-side support for sudo.

Adding sudo to a command can easily be handled by on the master-side. Also,
different people will have different expectations, which a single argument
isn't enough to capture.

See https://github.com/fabric/fabric/issues/503 for some discussions.

This reverts commit b5cbb73bdd1fae2fd19ac4e3e7c14aa27419cd4e, reversing
changes made to d0cd62b6049759d89b09b1512dab2268132fd30d.
Add support for passing keyword arguments to BuildFactory.addStep.

This was supported in old versions of buildbot, but there wasn't a release that
supported both, making transitioning harder than necessary.
Revert 'try_client_available_builder_names'.

This added ad-hoc support for overriding `getAvaliableBuilderNames` in a
subclass of `TrySchedulerer`. But that support was undocumented and untested.

This reverts commit 46a81edbecee41e9042b7d1bbf928e13d59e618d, reversing
changes made to 9ec2372129b48842b5c3bc5e933b28ed728d46e3.
Use `assertTrue`/`assertFalse` instead of `assertIdentical` where appropriate.
Merge 'support-depercated-addStep': Add support for passing keyword arguments to BuildFactory.addStep.

We deprecated this in 0.8.6 and dropped support in 0.8.7. But 0.8.7 was the
first version to support not needing to use .addFactoryArguments. But, passing
keyword arguments to .addStep also avoid this.
Don't use deprecated name SetProperty in regression tests.
Expose twisted.cred for change hook auth.

Twisted provides a rich interface for defining authentication. Use it
for defining change hook authorization, rather than just one specific
bit of it.
Also skip adding hook if it IUsernamePassword isn't supported.
Link to twisted.cred documentation.
Merge 'web-auth':  Expose twisted.cred for change hook auth.

Twisted provides a rich interface for defining authentication. Use it
for defining change hook authorization, rather than just one specific
bit of it.
Merge pull request #767 from tomprince/p4-cleanups

P4 cleanups