3750 Change Author to Creator and use tag name in headings

https://code.google.com/p/otwarchive/issues/detail?id=3750

* Made the display name "Creator Chose Not To Use Archive Warnings" instead of "Author Chose Not To Use Archive Warnings."
* On the /works page for `WARNING_DEFAULT_TAG_NAME`, the heading was using the display name "Author Chose Not To Use Archive Warnings" rather than the tag name "Choose Not To Use Archive Warnings." Now it should use "Choose Not To Use Archive Warnings," the actual name of the tag.