use return 0,<exp> to try to deal with comments.

The problem is JavaScript's idiotic automatic semicolon insertion.

If you have an expression like

```js
    return
     2
```

That's just returns undefined. So, if the user enters

```
// hello
t
```

That gets converted to

```js
return // hello
t
```

We used to try to strip linefeeds and comments and it mostly worked
but the comment stripper was simple because who the F wants to write
a whole effing parser just to strip comments.

As a try, if we change the generated code to

```js
return 0,// hello
t
```

The automatic semicolon insertion doesn't happen and it correctly
returns t.

src/ByteBeatCompiler.js

@@ -8,9 +8,9 @@ export default class ByteBeatCompiler {
 
   static removeCommentsAndLineBreaks(x) {
     // remove comments (hacky)
-    x = x.replace(/\/\/.*/g, ' ');
-    x = x.replace(/\n/g, ' ');
-    x = x.replace(/\/\*.*?\*\//g, ' ');
+    //x = x.replace(/\/\/.*/g, ' ');
+    //x = x.replace(/\n/g, ' ');
+    //x = x.replace(/\/\*.*?\*\//g, ' ');
     return x;
   }
 
@@ -326,7 +326,7 @@ export default class ByteBeatCompiler {
         } else {  // infix
           x = `
               return function(t, i, stack, window, extra) { 
-                  return ${ByteBeatCompiler.strip(x)};
+                  return 0,${ByteBeatCompiler.strip(x)};
               }`;
         }
       }