Merge pull request #53 from alphagov/dh_subs

Configurations for publications.dh and mediacentre.dh
sites.valid is not a directory
mkdir tmp
Initial set of dh_mediacentre mappings
Initial set of dh_publications mappings
removed blackisted mapping for dfid_consultation
Merge pull request #54 from alphagov/dh_sub_mappings

DH subdomain mappings mapping additions
removed blank line from mediacentre mappings
removed blank line from dh publications
New Home Office Mappings
Merge pull request #55 from rjc123/newmappings

New Home Office Mappings
Mustache robots.txt
404/418 mustache templates
Path to smoke_tests in README
tidy_mappings provides default status code
Tidy_mappings blanks 410 New Urls
site_host script
newer minitest
sites.valid is a file
removed subset test to large mod page