Render button

src/3x5.ts

@@ -1,3 +1,4 @@
+import { Button } from './lib/button';
 import { Card, CardVm, GetField } from './lib/card';
 import { Here, RegisterJumpHere } from './lib/debug';
 import { Expr } from './lib/expr';
@@ -121,7 +122,13 @@ function render() {
 
   const vm: CardVm = {
     mode: "render",
-    commands: { ...HTML, get: GetField, expr: Expr, here: Here },
+    commands: {
+      ...HTML,
+      get: GetField,
+      expr: Expr,
+      here: Here,
+      button: Button,
+    },
     output: "",
     card: theCard,
   };