Need for proper library documentation and other issues

[ayz4sci]

1. You guys need to properly document this library, I'm having to guess, infer things in your library. What does signature & policy mean?

2. The UX is poor for file uploads from local providers. After selecting an image or taking a picture, I don't know what to do next.

3. The Picasso used in the CloudListViewHolder(59) is failing, you should update it to the latest version. This fixed it for me Picasso.get().load(url).into(iconView);