Add SharedUploadedFile model to distribute work files between Mayan nodes easier
Add transaction.atomic, make sure the default language is used, return a list of versions not documents
Remove debug code, add TODO reminders, simplify new version creation method
Don't store OCR error log if no document was created
Use SharedUploadedFile model for background task, add task for creating versions of a document
Update document creation API call to use SharedUploadedFile model
Remove obsolete method from admin
Update source app views, model method and API calls to use the document app's models, managers.