Kill two compilation warnings

src/compilation.rs

@@ -3,7 +3,7 @@ extern crate llvm_sys;
 use std::collections::HashMap;
 
 use self::llvm_sys::prelude::*;
-use parser::{ParseResult, AST, ASTNode, Prototype, Function, Expression};
+use parser::{AST, ASTNode, Function, Expression};
 
 use llvm_wrap as LLVMWrap;
 

src/main.rs

@@ -114,7 +114,7 @@ fn repl_handler(input: &str, state: &mut InterpreterState) -> String {
     let mut result = String::new();
 
     let tokens = match tokenize(input) {
-        Err(e) => return format!("Tokenization error"),
+        Err(e) => return format!("Tokenization error: {}", e.msg),
         Ok(t) => t,
     };