Add slice swap benchmark.

Adds a benchmark of various different ways of swapping the elements of
two slices, including several implementations in C.

Change-Id: I7ff490aefee6edfe5d7630b851278ce1fc385e8c
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..62e269a
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,7 @@
+extern crate cty;
+extern crate num;
+
+mod bindings;
+
+pub mod cswap;
+pub mod swap;