Make exports consistent (#269)

* Make exports consistent

* Cleanup trie impl

packages/util/src/buffer/index.ts

@@ -2,11 +2,8 @@
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
-import bufferToU8a from './toU8a';
-
 /**
  * @summary Utility methods to convert to and from `Buffer` objects
  */
-export {
-  bufferToU8a
-};
+
+export { default as bufferToU8a } from './toU8a';