Add UKaea crest and assign BIS org colour

https://www.pivotaltracker.com/story/show/40939523
remove .DS_Store
removing uk-atomic-energy-authority from colours
Merge pull request #711 from alphagov/add-UKaea-crest

Add UKaea crest and assign BIS org colour

https://www.pivotaltracker.com/story/show/40939523