feat(transpiler): implement @IMPLEMENTS

tools/transpiler/spec/interfaces_spec.js

@@ -0,0 +1,22 @@
+import {ddescribe, describe, it, expect, IS_DARTIUM} from 'test_lib/test_lib';
+import {IMPLEMENTS} from './fixtures/annotations';
+
+class Interface1 {}
+class Interface2 {}
+
+@IMPLEMENTS(Interface1, Interface2)
+class SomeClass {}
+
+export function main() {
+  describe('interfaces', function() {
+    //TODO: remvoe when interfaces are supported in AtScript
+    if (IS_DARTIUM) {
+      it('should work', function () {
+        var s = new SomeClass();
+        expect(s instanceof Interface1).toBeTrue();
+        expect(s instanceof Interface2).toBeTrue();
+      });
+    }
+  });
+
+}