Merge branch 'master' of https://github.com/thoughtbot/administrate

* 'master' of https://github.com/thoughtbot/administrate:
  Tweak primary navigation (thoughtbot#861)
  Redesign focus outline styles (thoughtbot#863)
  Localise Dates (thoughtbot#570)
  Wrap unsupported form field notes in proper divs (thoughtbot#515)
  Update customizing_dashboards.md (thoughtbot#568)
  Wrap table cell contents instead of CSS truncation (thoughtbot#482)
  Remove worker from Procfile (thoughtbot#854)
  Remove dependency from ActionMailer (thoughtbot#851)
  Release version 0.6.0.
  Remove delayed_job_active_record dependency (thoughtbot#845)
  use the association includes in the has_many resources as well
  move include work to an association includes
  improve performance for n+1s