Adds the ability to check whether an attachment is a 'TNEF' formatted message.
Features
- Added 'DecodeSignedContent' method to 'MapiMessage'.
- Added API to check if 'subfolder' is from 'StandardIpmFolder'.
- Added the ability to check whether an attachment is a 'TNEF' formatted message.
- Improved working with StickyNote, DistList and IPM.Document.