add a component example

examples/component.rs

@@ -0,0 +1,27 @@
+extern crate xmpp;
+
+use xmpp::jid::Jid;
+use xmpp::component::ComponentBuilder;
+use xmpp::plugins::messaging::{MessagingPlugin, MessageEvent};
+
+use std::env;
+
+fn main() {
+    let jid: Jid = env::var("JID").unwrap().parse().unwrap();
+    let pass = env::var("PASS").unwrap();
+    let host = env::var("HOST").unwrap();
+    let port: u16 = env::var("PORT").unwrap().parse().unwrap();
+    let mut component = ComponentBuilder::new(jid.clone())
+                                         .password(pass)
+                                         .host(host)
+                                         .port(port)
+                                         .connect()
+                                         .unwrap();
+    component.register_plugin(MessagingPlugin::new());
+    loop {
+        let event = component.next_event().unwrap();
+        if let Some(evt) = event.downcast::<MessageEvent>() {
+            println!("{:?}", evt);
+        }
+    }
+}