IRust Repl

Repl engine used by IRust to interpret rust code

The core is println!("{:?}", expression) with tricks to conserve variables and context

Example:

```rust use irust_repl::{Repl, ToolChain};

let mut repl = Repl::new(ToolChain::Stable).unwrap(); repl.insert("let a = 5"); assert_eq!(repl.eval("a+a").unwrap().output, "10"); ```