Implicitly create a json response parser when using @Transform

Before this change, in order to use a `@Transform` annotation, you would have to create a boiler-plate response parser for json methods. Ex.

```java

   @GET
   @ResponseParser(AddressPage.class)
   @Transform(AddressPages.class)
   Iterator<ListPage<Address>> list();

   static final class AddressPage extends ParseJson<ListPage<Address>> {
      @Inject AddressPage(Json json) {
         super(json, new TypeLiteral<ListPage<Address>>() {
         });
      }
   }
```

This completely clutters the experience, as this can be easily taken care of. With this change, the above code is shortened, as it doesn't require you to declare the intermediate type.

```java
   @GET
   @Transform(AddressPages.class)
   Iterator<ListPage<Address>> list();
```