Remove buffer dependency

Closes #332

package.json

@@ -24,7 +24,6 @@
 	"dependencies": {
 		"babel-polyfill": "=6.23.0",
 		"browserify-bignum": "=1.3.0-2",
-		"buffer": "=5.0.6",
 		"bytebuffer": "=5.0.1",
 		"ed2curve": "=0.2.1",
 		"js-nacl": "LiskHQ/js-nacl#6dc1417",

src/crypto/convert.js

@@ -12,7 +12,6 @@
  * Removal or modification of this copyright notice is prohibited.
  *
  */
-import { Buffer } from 'buffer';
 import bignum from 'browserify-bignum';
 import ed2curve from 'ed2curve';
 import { getSha256Hash } from './hash';

src/index.js

@@ -19,7 +19,6 @@
  */
 import 'babel-polyfill';
 import naclFactory from 'js-nacl';
-import buffer from 'buffer';
 import crypto from './crypto';
 import dapp from './transactions/dapp';
 import delegate from './transactions/delegate';
@@ -32,8 +31,6 @@ import api from './api/liskApi';
 import slots from './time/slots';
 import mnemonic from './utils/mnemonic';
 
-global.Buffer = global.Buffer || buffer.Buffer;
-
 global.naclFactory = naclFactory;
 
 global.naclInstance = null;

src/utils/mnemonic.js

@@ -29,7 +29,6 @@
  */
 import bignum from 'browserify-bignum';
 import crypto from 'crypto';
-import { Buffer } from 'buffer';
 import wordList from './words';
 
 /**