API+

This contains changes from each of us. Most of the changes are me documenting the api and making it adhere to some conventions. I haven't documented the conventions yet.

This will break the UI, so it shouldn't be merged until I can update the UI and PR that too.

This PR contains all of the livetest changes as well.

My biggest concern at this point is that the renter doesn't have any way to communicate information about files. There's no indication of how expensive an upload will be. There's no indication of how much time a file has remaining. There's no indication of how many hosts are online who have the file (the 'health'). There's no way to repair a file. There's no safety mechanism to prevent the same piece from ending up on one host multiple times. Finally, the hostdb doesn't update automatically (and it probably should).

After we fix the deadlocking problems, this I think is the highest priority.