Adding DB to authors file.
Merge pull request #414 from edx/sanchez/add-db

Adding DB to authors file.
Add student training assessment information
Merge pull request #394 from edx/sylvia/docs/TIM-597

Add student training assessment information for course authors
Remove translation strings from assessment APIs
Updated logging in XBlock mixins
Added more verbose logging in assessment APIs
Cleaned up i18n strings in templates.
Add missing i18n strings
Add i18n to Travis build
Remove fake2 language, since we already have Esperanto
Merge pull request #408 from edx/will/i18n-strings-cleanup

i18n string cleanup
Use external submissions API
Move openassessment out of the apps directory
Use pkg_resources to check whether OA XBlock is installed.
Merge pull request #411 from edx/will/external-submissions-app

Will/external submissions app
Remove unused event logger config
Refactor assessment and workflow APIs
Moved workflow errors into a separate module.