Merge remote-tracking branch 'upstream/master' into fix-references-header-parsing

* upstream/master: (574 commits)
  remove dateFormat global exception
  fix relative paths to xterm.js within fit.js
  use setFixtures instead of fixture.set
  prevent u2f tests from triggering a form submission while testing
  simplify test for focus state
  preload projects.json fixture
  preload projects.json fixture
  rework tests which rely on teaspoon-specific behavior
  Only render hr when user can't archive project.
  use setFixtures instead of fixture.set
  ensure helper classes and constants are exposed globally
  preload projects.json fixture
  fix fixture references in environments_spec
  allow console.xxx in tests, reorder eslint rules alphabetically
  remove redundant "data-toggle" attribute so Vue doesn't complain
  fix broken reference to formatDate in a CommonJS environment
  fix errors within gl_dropdown_spec.js when running in Karma
  fix intermittant errors in merge_commit_message_toggle_spec.rb
  Update installation docs to include Docker, others
  ignore node_modules in rubocop
  ...