Remove FileManager #84
Description
I've much improved the handling of Blob data: it's now possible to pass an arbitrary number of Blobs embedded in your output schema, and these will be converted to JSON data with href and media_type with the actual data retrieved from a URL under /blob/. I've never used FileManager in anger, and it requires a bunch of slightly unsatisfying special-case code. I propose to remove FileManager and replace it with the Blob API.
Similarly, Blob replaces BlobOutput and I propose to make this change. I think we are still early enough in development that it's better to just make a breaking change than to keep old code and phase it out gradually.