New API for easier value reading from stdin

[dFionov]

Today reading value from stdin look like:

let a: i32 = stdin.lock().lines().next().unwrap().unwrap().trim().parse().unwrap();

As i think, Rust needs easier way to do this. E. g. like:

let a = stdin.read::<i32>().ok().expect("Write a number!");
let (b, c, d) = stdin.read::<(i32, f64, bool)>.ok().expect("Please, write integer, float and boolean!");

[steveklabnik]

https://crates.io/crates/text_io exists already, you may want to check it out.

[dFionov]

Not bad :) Thank you!