Merge pull request #3283 from pocesar/chai

export expect

chai/chai.d.ts

@@ -12,8 +12,8 @@ declare module chai {
         stack: string;
     }
 
-    function expect(target: any, message?: string): Expect;
-    
+    export function expect(target: any, message?: string): Expect;
+
     export var assert: Assert;
     export var config: Config;