Added @WithParams to specify kernel params in IT.

This pull request is intended to respond the issue #15 by adding the `@WithParams` annotation.

It could be used as follows:

```java
@WithParams({Kernel.NUUN_ROOT_PACKAGE, "io.nuun.kernel.tests"})
@RunWith(NuunITRunner.class)
public class NuunITRunnerTest
{
    
    @Inject
    ServiceA serviceA;
    
    @Test
    public void test()
    {
        assertThat(serviceA).isNotNull();
        serviceA.doSomethingUsefull();
    }
}
```

This annotation is used to specify kernel parameters in integration tests. In the example above it specify the packageRoots parameter.