This way we can have a handle of the errors in the high-level
components. Before they were implicitly discarded.

Also, spago build used now.

Not everything compiles yet.

Use thisModule everywhere.

This could be more performant than Array. We don't do random access,
only filtering.

This could be more performant than Array. We don't do random access,
only filtering.

Also, bump up purescript-spec-discover to 4.0.0 and make tests run.