bump promise-resolver, and simplify implementation

I released [email protected] a bit prematurely, and have already
cut 3.0.0. It now handles a number of corner cases we were handling
manually:

 1. Ensure callbacks are only called once
 2. Require a promise implementation if no callback is provided
 3. Ensure callbacks are called async

And a few we were missing:

 1. Look for `bluebird` and fallback to native promises
 2. Supress `unhandledRejection` notices on promises if user provides a callback (assumes the callback handles errors).
 3. Consistent behavior if they return a promise that is rejected with `null` / `undefined`
 4. Minor performance boost by only binding deferred.resolve/deferred.reject methods as needed

Closes #12

index.js

@@ -1,6 +1,5 @@
 'use strict';
 
-var once = require('once');
 var isPromise = require('is-promise');
 var promiseResolver = require('promise-resolver');
 
@@ -19,35 +18,27 @@ var promiseResolver = require('promise-resolver');
 module.exports = function (func, cb) {
   return function () {
     var async = false;
-    var promise = null;
-    cb = cb && once(cb);
-    if (typeof Promise !== 'undefined') {
-      promise = new Promise(function (resolve, reject) {
-        cb = promiseResolver(resolve, reject, cb);
-      });
-    } else if (!cb) {
-      throw new Error('No Native Promise Implementation: You must use a callback function or upgrade to Node >= 0.11.13');
-    }
+    var deferred = promiseResolver.defer(cb);
 
     try {
       var answer = func.apply({
         async: function () {
           async = true;
-          return cb;
+          return deferred.cb;
         }
       }, Array.prototype.slice.call(arguments));
 
       if (!async) {
         if (isPromise(answer)) {
-          answer.then(cb.bind(null, null), cb);
+          answer.then(deferred.resolve, deferred.reject);
         } else {
-          setImmediate(cb.bind(null, null, answer));
+          deferred.cb(null, answer);
         }
       }
     } catch (e) {
-      setImmediate(cb.bind(null, e));
+      deferred.cb(e);
     }
 
-    return promise;
+    return deferred.promise;
   }
 };

package.json

@@ -23,11 +23,10 @@
   "homepage": "https://github.com/SBoudrias/run-async",
   "dependencies": {
     "is-promise": "^2.1.0",
-    "once": "^1.3.0",
-    "promise-resolver": "^2.0.0"
+    "promise-resolver": "^3.0.0"
   },
   "devDependencies": {
-    "bluebird": "^2.10.2",
-    "mocha": "^2.3.3"
+    "mocha": "^2.3.3",
+    "pinkie": "^1.0.0"
   }
 }

test.js

@@ -7,7 +7,7 @@ var assert = require('assert');
 var runAsync = require('./index');
 
 describe('runAsync', function () {
-  var Promise = require('bluebird');
+  var Promise = require('pinkie');
 
   it('run synchronous method', function (done) {
     var ranAsync = false;
@@ -134,6 +134,6 @@ describe('runAsync', function () {
 
     assert.throws(function () {
       runAsync(returns)();
-    }, /No Native Promise Implementation/);
+    }, /No Promise Implementation/);
   });
 });