feat(client): proper proxy and tunneling in Client

Closes #774

src/mock.rs

@@ -12,7 +12,7 @@ use solicit::http::frame::{SettingsFrame, Frame};
 use solicit::http::connection::{HttpConnection, EndStream, DataChunk};
 
 use header::Headers;
-use net::{NetworkStream, NetworkConnector};
+use net::{NetworkStream, NetworkConnector, SslClient};
 
 #[derive(Clone, Debug)]
 pub struct MockStream {
@@ -315,3 +315,13 @@ impl NetworkConnector for MockHttp2Connector {
         Ok(self.streams.borrow_mut().remove(0))
     }
 }
+
+#[derive(Debug, Default)]
+pub struct MockSsl;
+
+impl<T: NetworkStream + Send + Clone> SslClient<T> for MockSsl {
+    type Stream = T;
+    fn wrap_client(&self, stream: T, _host: &str) -> ::Result<T> {
+        Ok(stream)
+    }
+}