apply one-sentence-per-line rule to the changed section
factor out integration-style step testing support
add an integration test that renders a new-style step
Tickle #2934
Fix checkLogfiles to not fail with new style steps
update documentation for GitHub change hook

* misc syntax, wording and cosmetic changes
* move mention of standalone server to the beginning of the section
* fix link to the GitHub tutorial for adding webhooks
* make list of parameters of GitHub webhook and their correpsonding
  values explicit

Fixes ticket:2938
Merge sa2ajj/buildbot:bugfix-2938 (PR #1253)
Fix cross-site scripting in status_json by specifying nosniff and app/json content
Merge pull request #1254 from djmitche/bug2934

Test for and fix new-style step assertions triggered by Buildbot code

Fixes ticket:2934
Merge pull request #1258 from wmswms/eight

Bugfix 2943: Fix cross-site scripting in status_json by specifying nosniff and app/js...

Fixes ticket:2943