remove es6-promise. closes #689

package.json

@@ -45,7 +45,6 @@
     "buble": "^0.6.4",
     "codecov.io": "^0.1.6",
     "console-group": "^0.2.0",
-    "es6-promise": "^3.0.2",
     "eslint": "^2.9.0",
     "estree-walker": "^0.2.0",
     "istanbul": "^0.4.0",

src/rollup.js

@@ -1,4 +1,3 @@
-import Promise from 'es6-promise/lib/es6-promise/promise.js';
 import { basename } from './utils/path.js';
 import { writeFile } from './utils/fs.js';
 import { keys } from './utils/object.js';

src/utils/first.js

@@ -1,5 +1,3 @@
-import Promise from 'es6-promise/lib/es6-promise/promise.js';
-
 // Return the first non-falsy result from an array of
 // maybe-sync, maybe-promise-returning functions
 export default function first ( candidates ) {

src/utils/fs.js

@@ -1,4 +1,3 @@
-import Promise from 'es6-promise/lib/es6-promise/promise.js';
 import * as fs from 'fs';
 import { dirname } from './path.js';
 

src/utils/promise.js

@@ -1,5 +1,3 @@
-import Promise from 'es6-promise/lib/es6-promise/promise.js';
-
 export function mapSequence ( array, fn ) {
 	let results = [];
 	let promise = Promise.resolve();

src/utils/transform.js

@@ -1,5 +1,3 @@
-import Promise from 'es6-promise/lib/es6-promise/promise.js';
-
 export default function transform ( source, id, transformers ) {
 	let sourceMapChain = [];