There are several defects due to the API of multipart-form-data, which
will need patching upstream. The Dream API needs simplification, in
particular Dream.begin_upload should be removed.
Get rid of the separate built_in sublibrary along the way, as it was
becoming an obstacle in the dependency graph.
The catch middleware was originally deleted as a separate middleware,
and eventually replaced by an internal middleware during error handler
unification. However, the plan is now to make that internal middleware
customizable, so restore it again as a middleware. It's still built-in,
but only as a default that can be changed.
- Accept a path-to-Dune-workspace option.
- Process multiple files in one run for easier Dune integration.
- Accumulate strings rather than printing them.
