Uploading Command now Operational

It's not exactly user friendly, and it's a bit tempermental as you go up in file size, but I clamped the max sector size for now. The current sector size should mean there will be no problems over local networks, haven't tested it on internet connections though (slower speeds may mean more problems).

With this PR, all that remains is proof of storage, which is 75% implemented anyway. Then we're technically done with the proof-of-concept, though it's buggy and halfway thrown together.