Merge pull request #21 from gusferguson/version_5-1-0_release-1

Remove Editor page from Help site - delete menu entry, html file, images
Adding a custom error page

The page redirects you to:
http://help.openmicroscopy.org/
merge master -Dorg -Isnoopycrimecop/ome-help:cname_staging -Snone: PR 23 (Adding a custom error page)
merge master -Dorg -Isnoopycrimecop/ome-help:cname_staging -Snone: branch snoopycrimecop:cname_staging
merge master -Dorg -Isnoopycrimecop/ome-help:cname_staging -Snone

Repository: openmicroscopy/ome-help
Already up-to-date.

Merged PRs:
  # PR 23 qidane 'Adding a custom error page'
Merged branches:
  # snoopycrimecop:cname_staging

Generated by OME-help-staging#25 (http://ci.openmicroscopy.org/job/OME-help-staging/25/)