Move the filetest harness into its own crate.

This allows us to run the tests via a library call rather than just
as a command execution. And, it's a step toward a broader goal, which
is to keep the code in the top-level src directory minimal, with
important functionality exposed as crates.

lib/filetests/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "cretonne-filetests"
+authors = ["The Cretonne Project Developers"]
+version = "0.3.4"
+description = "Test driver and implementations of the filetest commands"
+license = "Apache-2.0"
+documentation = "http://cretonne.readthedocs.io/en/latest/testing.html#file-tests"
+repository = "https://github.com/Cretonne/cretonne"
+publish = false
+
+[lib]
+name = "cton_filetests"
+
+[dependencies]
+cretonne = { path = "../cretonne", version = "0.3.4" }
+cretonne-reader = { path = "../reader", version = "0.3.4" }
+filecheck = { path = "../filecheck", version = "0.1.0" }
+num_cpus = "1.5.1"