Also ensure newline at EOF.
This was achieved by running the new normalize_coop_frontmatter.rb
script which basically reads in the frontmatter, parses it and dumps it
back out.
I had to manually fix some telephone numbers which had been incorrectly
parsed as some kind of number rather than as strings.
This script iterates over all of the coops to pull their clients from
the individual co-op pages, normalises the filenames of the images and
creates an entry under `_clients`.
