Import and export improved

- Import paths are now vname and not sym
- Imports and exports accept multiple space-delimited operators in []

as a result, we can now reliably import and export the operator *

- error reporting ergonomics

src/systems/io/facade.rs

@@ -145,7 +145,7 @@ impl<'a, P: MessagePort, ST: StreamTable + 'a> IntoSystem<'a>
       constants: io_bindings(i, streams).unwrap_tree(),
       code: embed_to_map::<IOEmbed>(".orc", i),
       prelude: vec![FileEntry::Import(vec![Import {
-        path: i.i(&vec![i.i("system"), i.i("io"), i.i("prelude")]),
+        path: vec![i.i("system"), i.i("io"), i.i("prelude")],
         name: None,
       }])],
       handlers,