Merge pull request #190 from rollup/import-promise-polyfill

Added missing import

src/utils/first.js

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