Hide quantize options if original image. Fixes #120.

src/components/Options/index.tsx

@@ -112,6 +112,8 @@ export default class Options extends Component<Props, State> {
 
     return (
       <div class={`${style.options}${className ? (' ' + className) : ''}`}>
+        {encoderState.type !== 'identity' && (
+          <div>
             <p>Quantization</p>
             <label>
               <input
@@ -129,6 +131,8 @@ export default class Options extends Component<Props, State> {
               />
             }
             <hr/>
+          </div>
+        )}
         <label>
           Mode:
           {encoderSupportMap ?