Fold runtime/ crate into this source tree

While I like the idea of having a runtime completely decoupled from the
syntax and compiler, I don't think this is that big of a project for
that to be necessary or even useful yet.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

src/compile/thunk.rs

@@ -1,8 +1,9 @@
 use crate::{
     compile::{error::*, Compile},
     syn::{ast::*, visit::*},
+    obj::prelude::*,
+    vm::inst::*
 };
-use runtime::{obj::prelude::*, vm::inst::*};
 use std::mem;
 
 pub enum Thunk {