[ADF-571] upload feature rework (#1922)

* upload feature rework

lots of improvements for upload dialog and underlying services

* readme update

- readme cleanup
- remove some old comments from code
- update readme with new events for Upload Service

* restore prerequisites section in readme

ng2-components/ng2-alfresco-upload/src/components/upload-button.component.ts

@@ -190,6 +190,7 @@ export class UploadButtonComponent implements OnInit, OnChanges {
                 error => this.onError.emit(error)
             );
         }
+        return 'Error';
     }
 
     // TODO: move to AlfrescoContentService
@@ -210,6 +211,23 @@ export class UploadButtonComponent implements OnInit, OnChanges {
         return Observable.throw(error || 'Server error');
     }
 
+    getFolderNode(nodeId: string): Observable<MinimalNodeEntryEntity> {
+        let opts: any = {
+            includeSource: true,
+            include: ['allowableOperations']
+        };
+
+        return Observable.fromPromise(this.apiService.getInstance().nodes.getNodeInfo(nodeId, opts))
+            .catch(err => this.handleError(err));
+    }
+
+    private handleError(error: Response) {
+        // in a real world app, we may send the error to some remote logging infrastructure
+        // instead of just logging it to the console
+        this.logService.error(error);
+        return Observable.throw(error || 'Server error');
+    }
+
     private hasCreatePermission(node: any): boolean {
         if (node && node.allowableOperations) {
             return node.allowableOperations.find(permision => permision === 'create') ? true : false;