Style options menu and fix leak in buttons' mapping

src/js/automaton.js

@@ -15,7 +15,7 @@ function Automaton(async, dom, messaging, screen, session, ui) {
 					ui.setTextSpeed(choices.textSpeed);
 				}}
 			],
-			cancel: startMenu,
+			cancel: function() {},
 			name: 'settings'
 		}
 	};
@@ -73,7 +73,6 @@ function Automaton(async, dom, messaging, screen, session, ui) {
 	}
 
 	function settings() {
-		screen.clear();
 		ui.menu(menus.settings);
 	}
 

src/screen.css

@@ -97,6 +97,25 @@ ul#startMenu {
 	width: 7em;
 }
 
+ul#settingsMenu {
+	position: absolute;
+	top: 0;
+	right: 0;
+	bottom: 0;
+	left: 0;
+}
+
+ul#textSpeedMenu, ul#layoutMenu {
+	position: absolute;
+	top: 50%;
+	left: 50%;
+	transform: translate(-50%, -50%);
+}
+
+ul#layoutMenu {
+	width: 20em;
+}
+
 ul#nameMenu {
 	width: 6em;
 }