Server question data structures

[msl5994]

Has methods for:

• getting the list of questions from the server
• getting a specific question from the list of questions
• updating questions on the server

[vteague]

Looks great, thanks. Two small issues that I'll raise as things to work on:

1. Background should be able to be added when you first upload a question.
2. We should do something to indicate that the question-edit has been successful, probably a bit like what we do when the initial question upload is successful.