relax Send + Sync constraint on Renderables; remove 3 format calls from render loop

maybe render should have mutable access after all?

tui/src/tui_output.rs

@@ -21,7 +21,7 @@ impl Output for TuiOut {
 }
 impl TuiOut {
     /// Spawn the output thread.
-    pub fn run_output <T: Render<TuiOut> + 'static> (
+    pub fn run_output <T: Render<TuiOut> + Send + Sync + 'static> (
         engine: &Arc<RwLock<Tui>>,
         state:  &Arc<RwLock<T>>,
         timer:  Duration