Vendor dependencies

Let's see how I like this workflow.

vendor/js-sys/tests/wasm/Boolean.rs

@@ -0,0 +1,25 @@
+use js_sys::*;
+use wasm_bindgen::JsCast;
+use wasm_bindgen::JsValue;
+use wasm_bindgen_test::*;
+
+#[allow(deprecated)]
+#[wasm_bindgen_test]
+fn new_undefined() {
+    assert_eq!(Boolean::new(&JsValue::undefined()).value_of(), false);
+}
+
+#[allow(deprecated)]
+#[wasm_bindgen_test]
+fn new_truely() {
+    assert_eq!(Boolean::new(&JsValue::from("foo")).value_of(), true);
+}
+
+#[allow(deprecated)]
+#[wasm_bindgen_test]
+fn boolean_inheritance() {
+    let b = Boolean::new(&JsValue::from(true));
+    assert!(b.is_instance_of::<Boolean>());
+    assert!(b.is_instance_of::<Object>());
+    let _: &Object = b.as_ref();
+}