* origin/ci280:
ci: Another round of fixes for random Ansible UI breakage in 2.7/2.8
ci: work around various broken aspects of Travis VM image
Use virtualenv Python for stub connections to workaround problem
ci: Ansible 2.8 requires Python 2.7.
tests: add 2.8 format async error timeout message
ansible: prevent tempfile.mkstemp() leaks.
update gitignore again
ci: try bumping more Travis jobs to Ansible 2.8.
add .*.pid to gitignore
tests: allow running without hdrhistograms library.
issue #578: update Changelog.
travis: exclude docs-master from CI
issue #589: ensure real FileService/PushFileService are in the docs
issue #589: ensure real FileService/PushFileService are in the docs
docs: add new contributor entry
issue #589: remove outdated/incomplete examples
issue #589: split services example out and make it run.