Merge branch 'master' into dev-master

* master: (98 commits)
  Enable Style/EmptyLines cop, remove redundant ones
  Update CHANGELOG
  Cache results from jQuery selectors to retrieve namespace name
  Fix import button when import fail due the namespace already been taken
  Fix snippets comments not displayed
  Fix emoji paths in relative root configurations
  Exclude requesters from Project#members, Group#members and User#members
  Upgrade Thin from 1.6.1 to 1.7.0.
  Many squashed commits
  Cache autocomplete results
  Upgrade Sidekiq from 4.1.2 to 4.1.4.
  Upgrade seed-fu from 2.3.5 to 2.3.6
  use has_many relationship with events
  Support creating a todo on issuables via API
  Expose target, filter by state as string
  Add todos API documentation and changelog
  Improve the request / withdraw access button
  Metrics for Rouge::Plugins::Redcarpet and Rouge::Formatters::HTMLGitlab
  Groundwork for Kerberos SPNEGO (EE feature)
  Update CHANGELOG 8.9.5 for runners related fixes
  ...