feat: add support for topic/auto-generated channels and fix minor parsing errors (#233)

* dev: add support for topic channels

* dev(parser): do not try to parse empty nodes

* dev: add support for auto-generated game channels

src/parser/classes/ThumbnailLandscapePortrait.ts

@@ -0,0 +1,15 @@
+import { YTNode } from '../helpers';
+import Thumbnail from './misc/Thumbnail';
+
+export default class ThumbnailLandscapePortrait extends YTNode {
+  static type = 'ThumbnailLandscapePortrait';
+
+  landscape: Thumbnail[];
+  portrait: Thumbnail[];
+
+  constructor (data: any) {
+    super();
+    this.landscape = Thumbnail.fromResponse(data.landscape);
+    this.portrait = Thumbnail.fromResponse(data.portrait);
+  }
+}