Fix robots.txt and noarchive uppercase; add tests.
Added U of Iowa's logo and as a partner. Fixes #600
Merge pull request #601 from jcushman/dev-ohnorobot

Fix robots.txt and noarchive uppercase; add tests.
Updated stats email template to use the 'users' term instead
of the 'members' term.
Merge branch 'develop' of github.com:harvard-lil/perma into develop