Add a test for elaborated types.

After the rewrite, this works.

Fixes #3

tests/expectations/elaborated.rs

@@ -0,0 +1,11 @@
+/* automatically generated by rust-bindgen */
+
+
+#![allow(non_snake_case)]
+
+
+pub type whatever_t = ::std::os::raw::c_int;
+extern "C" {
+    #[link_name = "_Z9somethingPKi"]
+    pub fn something(wat: *const whatever_t);
+}

tests/headers/elaborated.hpp

@@ -0,0 +1,5 @@
+namespace whatever {
+  typedef int whatever_t;
+}
+
+void something(const whatever::whatever_t *wat);