Start working on a version of compare based on json values.

This will be a better test because it will be testing that what we export to json is equivalent to the elisp AST generated from emacs. Because of these tests, we could also confidently use the wasm structure to elisp.

src/lib.rs

@@ -3,6 +3,7 @@
 #![feature(path_file_prefix)]
 #![feature(is_sorted)]
 #![feature(test)]
+#![feature(iter_intersperse)]
 // TODO: #![warn(missing_docs)]
 #![allow(clippy::bool_assert_comparison)] // Sometimes you want the long form because its easier to see at a glance.