Add test coverage for submission failures.

Respond to both web requests and API requests.
Remove unused submission view.

New submissions are submitted via the API using the `et` gem.
Use header tags consistently among pages.

The <h1> tag is used for the name of the application and <h2> tags
to describe the per-page contents.
Remove unnecessary padding.
Change styling for <ul> elements.

They look similar to the tables.
Merge pull request #101 from atsheehan/minor_tweaks

Minor tweaks