Changes for the rus for rubyist book

gistfile1.txt

Multiple chapters:
        int::to_str(num) --->> std::int::to_str(num)

Chapter 6:
	int::range(1, 101) --->> std::int::range(1, 101)

Chapter 7:
	use core::pipes::{stream, Port, Chan} --->> Nothing?
	extern mod std; --->> extern mod extra;
	use std::comm::DuplexStream; --->> use extra:comm::DuplexStream;

Chapter 10:
	 This fails: "another_vector += a_vector;",
	 and this works: "another_vector = another_vector + a_vector;",
	 I don't know why.

Chapter 11:
	v.each --->> v.iter().advance
	impl IndustrialRaverMonkey: Monster --->> impl Monster for IndustrialRaverMonkey

Chapter 12:
	use core::io::{Reader, ReaderUtil}; --->> Nothing?
	io:: --->> std::io::
	... annoying from Ruby is that you ... --->> Should be Rust?
	extern mod core; use core::*; --->> Core should be std?

	io::stdin() --->> std::io::stdin()
	int::from_str(in) --->> std::int::from_str(in)
	int::to_str(number_string) --->> std::int::to_str(number_string)
	core::rand::RngUtil --->> std::rand::RngUtil
	etc...

	let rng = rand::Rng(); --->> let mut rng = rand::rng();

	let num = rng.gen_int() % 100 + 1; --->> Gave me errors, solved using: "let mut num: int = rng.gen(); num = num % 100 + 1;",
	can probably be solved better.