Split Server::listen into two methods to hack around ICE related to default type params

Trying to default the type parameters leads to an ICE and strange type errors.
I think this is just due to the experimental state of default type params and
this change can be rolled back when they are fixed.

src/server/mod.rs

@@ -46,11 +46,14 @@ impl Server<HttpListener> {
 
 impl<L: NetworkListener<S, A>, S: NetworkStream, A: NetworkAcceptor<S>> Server<L> {
     /// Binds to a socket, and starts handling connections.
-    pub fn listen<S, A, H, L>(self, handler: H) -> HttpResult<Listening<A>>
-    where S: NetworkStream,
+    ///
+    /// This method has unbound type parameters, so can be used when you want to use
+    /// something other than the provided HttpStream, HttpAcceptor, and HttpListener.
+    pub fn listen_network<H, S, A, L>(self, handler: H) -> HttpResult<Listening<A>>
+    where H: Handler<A, S>,
+          S: NetworkStream,
           A: NetworkAcceptor<S>,
-          H: Handler<A, S>,
-          L: NetworkListener<S, A> {
+          L: NetworkListener<S, A>, {
         let mut acceptors = Vec::new();
         let mut sockets = Vec::new();
         for (ip, port) in self.pairs.move_iter() {
@@ -76,6 +79,11 @@ impl<L: NetworkListener<S, A>, S: NetworkStream, A: NetworkAcceptor<S>> Server<L
             sockets: sockets,
         })
     }
+
+    /// Binds to a socket and starts handling connections.
+    pub fn listen<H: Handler<HttpAcceptor, HttpStream>>(self, handler: H) -> HttpResult<Listening<HttpAcceptor>> {
+        self.listen_network::<H, HttpStream, HttpAcceptor, HttpListener>(handler)
+    }
 }
 
 /// An iterator over incoming connections, represented as pairs of