Revised file processing screens on the backside of miniLock

Here is an implementation of the human interface design mentioned in issue #42.

And 3 videos that show it off:

Alice encrypts passport to Bob
https://vimeo.com/101773171

Save a secret song for my parents
https://vimeo.com/101773412

Crazy Town
https://vimeo.com/101773420
I just noticed this. This is really bad, please don't rely on parsing the localization string of an error message to determine if an error has occurred! You're contributing to security software here. This is unacceptable.