start program without spawning thread so screen works on mac. improve mouse demo

crsn/src/runtime/run_thread.rs

@@ -48,13 +48,15 @@ impl RunThread {
         self.info.cycle_time = cycle_time;
     }
 
-    pub fn start(self) -> JoinHandle<()> {
+    /// Spawn as a thread
+    pub fn spawn(self) -> JoinHandle<()> {
         std::thread::spawn(move || {
             self.run();
         })
     }
 
-    fn run(mut self) {
+    /// Start synchronously
+    pub fn run(mut self) {
         'run: loop {
             match self.eval_op() {
                 Ok(EvalRes { cycles, advance }) => {