Add some scaffolding for building more crates.

The src/tools directory contains the cretonne-tools crate which will build
binaries for testing cretonne.

The src/libctonfile directory contains the ctonfile library crate which
provides reading and writing of .cton files.

cranelift/src/libctonfile/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+authors = ["The Cretonne Project Developers"]
+name = "ctonfile"
+version = "0.0.0"
+publish = false
+
+[lib]
+name = "ctonfile"
+path = "lib.rs"
+
+[dependencies]
+cretonne = { path = "../libcretonne" }

cranelift/src/libctonfile/lib.rs

@@ -0,0 +1,12 @@
+
+// ====------------------------------------------------------------------------------------==== //
+//
+// Cretonne file read/write library
+//
+// ====------------------------------------------------------------------------------------==== //
+//
+// The libctonfile library supports reading and writing .cton files. This functionality is needed
+// for testing Cretonne, but is not essential for a JIT compiler.
+
+extern crate cretonne;
+pub mod parser;

cranelift/src/libctonfile/parser.rs

@@ -0,0 +1,2 @@
+
+use cretonne;