Fix unused imports in the tutorials

Author: alexcrichton

doc/rust.md

@@ -1611,7 +1611,6 @@ The following are examples of structure expressions:
 # struct Point { x: float, y: float }
 # struct TuplePoint(float, float);
 # mod game { pub struct User { name: &str, age: uint, score: uint } }
-# use game;
 Point {x: 10f, y: 20f};
 TuplePoint(10f, 20f);
 let u = game::User {name: "Joe", age: 35u, score: 100_000};

doc/tutorial-tasks.md

@@ -468,7 +468,6 @@ Here is the function that implements the child task:
 
 ~~~~
 # use std::comm::DuplexStream;
-# use comm::{Port, Chan};
 fn stringifier(channel: &DuplexStream<~str, uint>) {
     let mut value: uint;
     loop {
@@ -491,7 +490,6 @@ Here is the code for the parent task:
 
 ~~~~
 # use std::comm::DuplexStream;
-# use comm::{Port, Chan};
 # use task::spawn;
 # fn stringifier(channel: &DuplexStream<~str, uint>) {
 #     let mut value: uint;

doc/tutorial.md

@@ -2270,7 +2270,9 @@ fn chicken_farmer() {
     // The same, but name it `my_chicken`
     use my_chicken = farm::chicken;
     ...
+# my_chicken();
 }
+# chicken();
 # }
 ~~~