remove references to babel-polyfill and source-map-support/register f…

…rom within the code files

.travis.yml

@@ -1,6 +1,5 @@
 language: node_js
 node_js:
-  - "4"
   - "6"
   - "8"
   - "10"

src/Client.js

@@ -1,6 +1,3 @@
-import 'babel-polyfill';
-import 'source-map-support/register';
-
 import * as protocol from 'json-rpc-protocol';
 import log from 'debug';
 import net from 'net';

src/Server.js

@@ -1,6 +1,3 @@
-import 'babel-polyfill';
-import 'source-map-support/register';
-
 import * as protocol from 'json-rpc-protocol';
 import EventEmitter from 'events';
 import fs from 'fs';

src/index.js

@@ -1,5 +1,2 @@
-import 'babel-polyfill';
-import 'source-map-support/register';
-
 export * from './Client';
 export * from './Server';