Speed up Q.all

In the case where either:

 a) Not all values in the input array are promises (many orders of magnitude improvement)
 b) Some of the promises are already resolve (about twice as quick).

It does this by not waiting till the next turn of the event loop when it is un-necessary to do so.

Deferred will already ensure that the overall behaviour of all is correct with regard to resolving exactly once.

q.js

@@ -1227,13 +1227,20 @@ function all(promises) {
         }
         var deferred = defer();
         array_reduce(promises, function (undefined, promise, index) {
-            when(promise, function (value) {
-                promises[index] = value;
+            if (isFulfilled(promise)) {
+                promises[index] = valueOf(promise);
                 if (--countDown === 0) {
                     deferred.resolve(promises);
                 }
-            })
-            .fail(deferred.reject);
+            } else {
+                when(promise, function (value) {
+                    promises[index] = value;
+                    if (--countDown === 0) {
+                        deferred.resolve(promises);
+                    }
+                })
+                .fail(deferred.reject);
+            }
         }, void 0);
         return deferred.promise;
     });