Clientside/Offline Transcription

_From @cubap on October 16, 2015 19:35_

Vanilla T-PEN requires membership and authentication to attempt transcription or save new annotations. However, the discrete front-end would only truly require a connection to T-PEN to save annotations to rerum.io, attempt auto-parsing, and authenticate collaboration. This means that it could be adapted to run only on the client without these services as an offline app.
### Possible Options
- Single session use with a JSON output
- LocalStorage use for local data storage of JSON
- Synchronization after later reconnection
- Non-desktop app development
- Load image files from local disk

_Copied from original issue: cubap/TPEN3#14_