feat(test): Add an external version of the test library

Adds test adapters for TypeScript and JavaScript only, exported
as part of the test_lib module. These work with the Jasmine test
framework, and allow use of the test injector within test blocks
via the `inject` function.

See #4572, #4177, #4035, #2783

This includes the TestComponentBuilder. It allows using the
test injector with Jasmine bindings, and waits for returned
promises before completing async test blocks.

modules/angular2/test/test_lib/test_lib_public_spec.dart

@@ -0,0 +1,7 @@
+library angular2.test.test_lib.test_lib_public_spec;
+
+/**
+ * This is intentionally left blank. The public test lib is only for TS/JS
+ * apps.
+ */
+main() {}