fix(data-table): td-data-table-column return proper name in sort event (

#353)

the td-data-table-column wasnt setting the name properly and getting it from a global name

src/platform/core/data-table/data-table-column/data-table-column.component.ts

@@ -93,7 +93,7 @@ export class TdDataTableColumnComponent {
   }
 
   handleSortBy(): void {
-    this.onSortChange.emit({name: name, order: this._sortOrder});
+    this.onSortChange.emit({name: this.name, order: this._sortOrder});
   }
 
   isAscending(): boolean {