chore(build): update TypeScript version to unreleased beta

Also fixup the typings which were broken by changes in typescript's lib.d.ts

modules/angular2/globals.ts

@@ -19,6 +19,5 @@ interface Window {
   JSON: typeof JSON;
   Math: typeof Math;
   assert: typeof assert;
-  NaN: typeof NaN;
   gc(): void;
 }

modules/angular2/src/facade/math.ts

@@ -6,4 +6,4 @@ import {global} from 'angular2/src/facade/lang';
 export var __esModule = true;
 
 export var Math = global.Math;
-export var NaN = global.NaN;
+export var NaN = typeof NaN;

modules/angular2/tsd.json

@@ -72,9 +72,6 @@
     "selenium-webdriver/selenium-webdriver.d.ts": {
       "commit": "be0b6b394f77a59e192ad7cfec18078706e44db5"
     },
-    "touch-events/touch-events.d.ts": {
-      "commit": "055b3172e8eb374a75826710c4d08677872620d3"
-    },
     "zone/zone.d.ts": {
       "commit": "055b3172e8eb374a75826710c4d08677872620d3"
     }