Fix a bug with the bottom section

cyber-slides/src/main.rs

@@ -191,7 +191,7 @@ impl CyberScreenState {
                 (old, step)
             }
             Position::Bottom => {
-                let old = self.middle.replace(step.clone());
+                let old = self.bottom.replace(step.clone());
                 (old, step)
             }
         };

script.yml

@@ -11,7 +11,7 @@
     nanos: 0
 
 - text: Science is our Magic.
-  position: middle
+  position: bottom
   transition:
     secs: 1
     nanos: 0