Table: check columns_options before using it

src/components/Table.js

@@ -17,7 +17,7 @@ export default initial_vnode => {
 		}))
 		// merge column options
 		columns = columns.map(
-			column => column.label in initial_vnode.attrs.columns_options
+			column => initial_vnode.attrs.columns_options && column.label in initial_vnode.attrs.columns_options
 				? {...initial_vnode.attrs.columns_options[column.label], ...column} : column
 		).filter(column => !('display' in column) || column.display != false)
 	}