Promises (first look)

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Small fixes

vendors/Q/design/q6.js

@@ -0,0 +1,64 @@
+
+var isPromise = function (value) {
+    return value && typeof value.then === "function";
+};
+
+var defer = function () {
+    var pending = [], value;
+    return {
+        resolve: function (_value) {
+            if (pending) {
+                value = ref(_value);
+                for (var i = 0, ii = pending.length; i < ii; i++) {
+                    value.then.apply(value, pending[i]);
+                }
+                pending = undefined;
+            }
+        },
+        promise: {
+            then: function (_callback, _errback) {
+                var result = defer();
+                // provide default callbacks and errbacks
+                _callback = _callback || function (value) {
+                    // by default, forward fulfillment
+                    return value;
+                };
+                _errback = _errback || function (reason) {
+                    // by default, forward rejection
+                    return reject(reason);
+                };
+                var callback = function (value) {
+                    result.resolve(_callback(value));
+                };
+                var errback = function (reason) {
+                    result.resolve(_errback(reason));
+                };
+                if (pending) {
+                    pending.push([callback, errback]);
+                } else {
+                    value.then(callback, errback);
+                }
+                return result.promise;
+            }
+        }
+    };
+};
+
+var ref = function (value) {
+    if (value && typeof value.then === "function")
+        return value;
+    return {
+        then: function (callback) {
+            return ref(callback(value));
+        }
+    };
+};
+
+var reject = function (reason) {
+    return {
+        then: function (callback, errback) {
+            return ref(errback(reason));
+        }
+    };
+};
+