Delete original draft of shell

This draft of the shell was written a while ago and was not used in
redox. After this commit I intend to merge the shell from redox into
this repository.

src/bin/ion.rs

-extern crate ion;
-
-fn main() {
-    loop {
-        ion::repl()
-    }
-}

src/command.rs

-use std::process::{Command,Output};
-
-pub struct InstructionOut {
-    pub stdout: String,
-    pub stderr: String,
-}
-
-pub fn run(args: &[&str]) -> Option<InstructionOut> {
-    let output: Option<Output>;
-    match args.len() {
-        0 => output = Command::new("").output().ok(),
-        1 => output = Command::new(&args[0]).output().ok(),
-        _ => output = Command::new(&args[0]).args(&args[1..]).output().ok(),
-    }
-    if output.is_some() {
-        let output = output.unwrap();
-        Some(InstructionOut {
-            stdout: String::from_utf8(output.stdout).ok().expect("No stdout"),
-            stderr: String::from_utf8(output.stderr).ok().expect("No stderr"),
-        })
-    } else {
-        None
-    }
-}

src/lib.rs

-#![feature(convert)]
-pub mod command;
-
-use std::io;
-use command::*;
-
-pub fn repl() {
-    let mut input = String::new();
-    match io::stdin().read_line(&mut input) {
-        Ok(_) => {
-            let out_wrap = run(input.trim().split_whitespace().collect::<Vec<&str>>().as_slice());
-            if out_wrap.is_some() {
-                let out = out_wrap.unwrap();
-                if out.stdout.is_empty() {
-                    println!("{}",out.stderr.trim());
-                } else {
-                    println!("{}",out.stdout.trim());
-                }
-            } else {
-                println!("{} is not a valid command", input.trim());
-            }
-        }
-        Err(error) => println!("Line Read Error: {}", error)
-    };
-}