Fix some clippy warnings

src/main.rs

     mouse_pressed: bool,
 }
 
-fn handle_event(event: Event, map: &mut MapViewGl, input_state: &mut InputState, sources: &mut TileSources) -> Action {
-    match event {
+fn handle_event(event: &Event, map: &mut MapViewGl, input_state: &mut InputState, sources: &mut TileSources) -> Action {
+    match *event {
         Event::Closed => Action::Close,
         Event::Awakened => Action::Redraw,
         Event::MouseInput(ElementState::Pressed, MouseButton::Left, position) => {
 
         let mut redraw = false;
 
-        match handle_event(event, &mut map, &mut input_state, &mut sources) {
+        match handle_event(&event, &mut map, &mut input_state, &mut sources) {
             Action::Close => break 'outer,
             Action::Redraw => {
                 redraw = true;
         }
 
         for event in window.poll_events() {
-            match handle_event(event, &mut map, &mut input_state, &mut sources) {
+            match handle_event(&event, &mut map, &mut input_state, &mut sources) {
                 Action::Close => break 'outer,
                 Action::Redraw => {
                     redraw = true;
                     std::thread::sleep(dur);
 
                     for event in window.poll_events() {
-                        match handle_event(event, &mut map, &mut input_state, &mut sources) {
+                        match handle_event(&event, &mut map, &mut input_state, &mut sources) {
                             Action::Close => break 'outer,
                             Action::Redraw => {
                                 redraw = true;

src/tile_loader.rs

 
         TileLoader {
             client: None,
-            join_handle: thread::spawn(move || Self::work(request_rx, result_tx, notice_func)),
+            join_handle: thread::spawn(move || Self::work(&request_rx, &result_tx, notice_func)),
             request_tx: request_tx,
             result_rx: result_rx,
             pending: HashSet::new(),
     }
 
     fn work<F>(
-        request_rx: mpsc::Receiver<LoaderMessage>,
-        result_tx: mpsc::Sender<(Tile, Option<DynamicImage>)>,
+        request_rx: &mpsc::Receiver<LoaderMessage>,
+        result_tx: &mpsc::Sender<(Tile, Option<DynamicImage>)>,
         notice_func: F,
     )
         where F: Fn(Tile) + Sync + Send + 'static,
                     Some(request) => {
                         match image::open(&request.path) {
                             Ok(img) => {
-                                if let Err(_) = result_tx.send((request.tile, Some(img))) {
+                                if result_tx.send((request.tile, Some(img))).is_err() {
                                     break 'outer;
                                 }
                                 arc_notice_func(request.tile);
 
         let tile = Tile::new(tile_coord, source.id());
 
-        if !self.pending.contains(&tile) {
-            if self.request_tx.send(LoaderMessage::GetTile(
-                    TileRequest {
-                        tile: tile,
-                        url: source.remote_tile_url(tile_coord),
-                        path: source.local_tile_path(tile_coord),
-                        write_to_file: write_to_file,
-                    }
-                )).is_ok()
-            {
-                self.pending.insert(tile);
-            }
+        if !self.pending.contains(&tile) &&
+            self.request_tx.send(LoaderMessage::GetTile(
+                TileRequest {
+                    tile: tile,
+                    url: source.remote_tile_url(tile_coord),
+                    path: source.local_tile_path(tile_coord),
+                    write_to_file: write_to_file,
+                }
+            )).is_ok()
+        {
+            self.pending.insert(tile);
         }
     }