Include a UI test module with integration tests for serialization

[Artur-]

Serialization has been tested manually using https://dev.vaadin.com/attachment/ticket/19462/vaadin-demo.zip (removing spring security which is not serializable). The UI should be included in the project and an IT should be run automatically during build to verify that the application works

[pleku]

Serialization is presumable fixed for 1.1.1 with #158 , but this test is a top priority before doing any furher features for Spring add-on.