[no-issue] error image resolver mimetype should not be part of datatable (#3415)

* move error image custom logic form datatable to documentlist

* change travis

* [fix-test-log] added optional function to data row interface

* [no-issue] fixed datatable tests

* [no-issue] fixing tests

demo-shell/src/app/components/files/files.component.ts

@@ -178,6 +178,7 @@ export class FilesComponent implements OnInit, OnChanges, OnDestroy {
     supportedPages: number[];
     currentSiteid = '';
     warnOnMultipleUploads = false;
+    thumbnails = false;
 
     private onCreateFolder: Subscription;
     private onEditFolder: Subscription;
@@ -213,6 +214,11 @@ export class FilesComponent implements OnInit, OnChanges, OnDestroy {
         return this.folderUpload;
     }
 
+    toggleThumbnails() {
+        this.thumbnails = !this.thumbnails;
+        this.documentList.reload();
+    }
+
     ngOnInit() {
         if (!this.pagination) {
             this.pagination = <Pagination>{