Preparation for sharing

- rustfmt
- clippy
- comments
- README

src/interpreter/mod.rs

@@ -1,8 +1,8 @@
 mod apply;
-mod error;
 mod context;
+mod error;
 mod run;
 
 pub use context::{Context, Return};
 pub use error::RuntimeError;
-pub use run::{run, run_handler, Handler, HandlerParm, HandlerRes};
+pub use run::{run, run_handler, Handler, HandlerParm, HandlerRes};