Rewrote synchronous inspection code

Pulling in the latest from 'then/promise' forced a re-write of the synchronous
inspection code.

Author: John Haley

src/core.js

@@ -140,6 +140,33 @@ Promise.prototype._finale = function () {
   this._deferreds = null
 }
 
+/**
+ * Synchronous Inspection
+ */
+Promise.prototype.isPending = function () {
+  return this._state === 0;
+}
+Promise.prototype.isFulfilled = function () {
+  return this._state === 1 || this._state === 3;
+}
+Promise.prototype.isRejected = function () {
+  return this._state === 2;
+}
+Promise.prototype.value = function () {
+  if (!self.isFulfilled()) {
+    throw new Error('Cannot get a value of an unfulfilled promise.')
+  }
+
+  return this._value;
+}
+Promise.prototype.reason = function () {
+  if (!self.isRejected()) {
+    throw new Error('Cannot get a rejection reason of a non-rejected promise.')
+  }
+
+  return this._value;
+}
+
 
 function Handler(onFulfilled, onRejected, promise){
   this.onFulfilled = typeof onFulfilled === 'function' ? onFulfilled : null
@@ -168,4 +195,4 @@ function doResolve(fn, promise) {
     done = true
     promise._reject(LAST_ERROR)
   }
-}
+}