Document: Refactor behaviors to be a package with separate modules.
Cleanup: Docstrings, spelling.
Add assertion to existing test that didn't have one.
Extract document metadata into separate behavior.
Re-add previously removed FileOrPaperValidator.
Merge pull request #278 from 4teamwork/lg-extract-document-metadata-into-behavior

Extract document metadata into separate behavior
Add IAnnotationsJournalizable to ftw.mail.mail.
Add tabbeview (Preview / Journal / Info) as default view for ftw.mail.mail.
Add journal entry on mail