Preliminary promise implementation.

src/messages.js

Index: src/messages.js
diff --git a/src/messages.js b/src/messages.js
index 926f294ae870ee39d54b38fe34392b624d65bf31..a2c4ff0cce3a867007289d98d30af72b8bedacff 100644
--- a/src/messages.js
+++ b/src/messages.js
@@ -109,6 +109,9 @@ var kMessages = {
   invalid_argument:              ["invalid_argument"],
   data_view_not_array_buffer:    ["First argument to DataView constructor must be an ArrayBuffer"],
   constructor_not_function:      ["Constructor ", "%0", " requires 'new'"],
+  not_a_promise:                 ["%0", "is not a promise"],
+  promise_not_pending:           ["Promise", "%0", "already resolved or rejected"],
+  promise_cyclic:                ["Chaining cycle detected for promise", "%0"],
   // RangeError
   invalid_array_length:          ["Invalid array length"],
   invalid_array_buffer_length:   ["Invalid array buffer length"],