Implement clone manually

The Clone implementation for Handle does not need the T: Clone bound.

src/lib.rs

@@ -483,13 +483,22 @@ impl<'a, T> Drop for WebView<'a, T> {
 /// A thread-safe handle to a [`WebView`] instance. Used to dispatch closures onto its task queue.
 ///
 /// [`WebView`]: struct.WebView.html
-#[derive(Clone)]
 pub struct Handle<T> {
     inner: *mut CWebView,
     live: Weak<RwLock<()>>,
     _phantom: PhantomData<T>,
 }
 
+impl<T> Clone for Handle<T> {
+    fn clone(&self) -> Self {
+        Handle {
+            inner: self.inner,
+            live: self.live.clone(),
+            _phantom: PhantomData,
+        }
+    }
+}
+
 impl<T> Handle<T> {
     /// Schedules a closure to be run on the [`WebView`] thread.
     ///