Add deploy script

This automates the process of updating the production site to reduce the
chance of deploying without manually fixing the CNAME file
Merge branch 'master' into prod
Show what commands are being run by the deploy script
Merge branch 'master' into prod
Remove CNAME modding from deploy script

This is not necessary as the commit which fixes the CNAME file for prod
is only present in the prod repo, so will not be overwritten by any merge
from the dev repo.
Merge branch 'master' into prod