stdlib: Use Conlang module layout

stdlib/std.cl

@@ -1,10 +1,12 @@
 //! # The Conlang Standard Library
 
 pub mod preamble {
-    pub use super::num::*;
+    pub use super::{num::*, str::str};
 }
 
 pub mod num;
 
+pub mod str;
+
 #[cfg("test")]
 mod test;

stdlib/std/str.cl

@@ -0,0 +1,4 @@
+//! TODO: give conland a string type
+use super::num::u8;
+
+type str = [u8];