fix thumbnails option

docs/assets/example/index.js

@@ -77,8 +77,6 @@ var art = new Artplayer({
     thumbnails: {
         url: '/assets/sample/thumbnails.png',
         number: 100,
-        width: 160,
-        height: 90,
         column: 10,
     },
     subtitle: {

docs/assets/example/thumbnail.js

@@ -10,8 +10,6 @@ $artplayer.innerHTML = 'Drop video file here or click to upload.';
 var thumbnail = new ArtplayerToolThumbnail({
     fileInput: $artplayer,
     number: 60, // 数量
-    width: 160, // 宽度
-    height: 90, // 高度
     column: 10, // 列数
     begin: 0, // 开始
     end: NaN, // 结束
@@ -62,8 +60,6 @@ thumbnail.on('done', function () {
         thumbnails: {
             url: thumbnail.thumbnailUrl,
             number: thumbnail.option.number,
-            width: thumbnail.option.width,
-            height: thumbnail.option.height,
             column: thumbnail.option.column,
         },
     });