Update transformation tests following cnxmlutils changes

- Revert section title transformations
- Discard cnxml @type and generated @data-label in html
Merge pull request #240 from Connexions/fix-tests

Update transformation tests following cnxmlutils changes
redirect legacy filenames to resource urls
grr errant pdb
Merge pull request #242 from Connexions/filename-redirect

Redirect legacy filenames to resource urls
Always return default Access-Control-Allow-Headers whitelist

This avoids OPTIONS requests sometimes disallowed because of missing
Access-Control-Allow-Headers, probably due to cached response of
reqeuests without Access-Control-Request-Headers.
Merge pull request #243 from Connexions/add-access-control-allow-headers-whitelist

Always return default Access-Control-Allow-Headers whitelist
Ignore case when checking for english stopwords. Addresses #247
Merge pull request #248 from Connexions/fix-stopwords

Ignore case when checking for english stopwords. Addresses #247