feat(facade): toUpperCase and toLowerCase

modules/angular2/src/facade/lang.dart

@@ -64,6 +64,14 @@ class StringWrapper {
     return s.replaceAll(from, replace);
   }
 
+  static String toUpperCase(String s) {
+    return s.toUpperCase();
+  }
+
+  static String toLowerCase(String s) {
+    return s.toLowerCase();
+  }
+
   static startsWith(String s, String start) {
     return s.startsWith(start);
   }

modules/angular2/src/facade/lang.ts

@@ -104,6 +104,10 @@ export class StringWrapper {
     return s.replace(from, replace);
   }
 
+  static toUpperCase(s: string): string { return s.toUpperCase(); }
+
+  static toLowerCase(s: string): string { return s.toLowerCase(); }
+
   static startsWith(s: string, start: string) { return s.startsWith(start); }
 
   static substring(s: string, start: int, end: int = null) {

modules/angular2/test/facade/lang_spec.js

@@ -1,7 +1,7 @@
 import {describe, it, expect, beforeEach, ddescribe, iit, xit, el} from 'angular2/test_lib';
 
 import {ListWrapper} from 'angular2/src/facade/collection';
-import {isPresent, RegExpWrapper, RegExpMatcherWrapper, CONST_EXPR} from 'angular2/src/facade/lang';
+import {isPresent, RegExpWrapper, RegExpMatcherWrapper, StringWrapper, CONST_EXPR} from 'angular2/src/facade/lang';
 
 export function main() {
   describe('RegExp', () => {
@@ -29,4 +29,25 @@ export function main() {
     })
   });
 
+  describe('String', () => {
+    var upper, lower;
+
+    beforeEach(() => {
+      upper = 'SOMETHING'
+      lower = 'something';
+    });
+
+    it('should upper case a string', () => {
+      var str = StringWrapper.toUpperCase(lower);
+
+      expect(str).toEqual(upper);
+    });
+
+    it('should lower case a string', () => {
+      var str = StringWrapper.toLowerCase(upper);
+
+      expect(str).toEqual(lower);
+    });
+  });
+
 }