execute @Before annotated methods before REST requests

patched HttpJUnitRunner to support this
added @HttpConfig annotation and RuleStrategy enum to configure behavior
default behavior is unchanged

example:
```java
@RunWith(HttpJUnitRunner.class)
@HttpConfig(ruleStrategy=RuleStrategy.HTTP_CALL_AFTER_BEFORE)
public class MyTest {
	@Rule
	public Destination destination = new Destination(this, "http://localhost:" + System.getProperty( "org.osgi.service.http.port" ));
	
	@Context
	private Response response;
	
	@Before
	public void before() {
		System.err.println("Test#before()");
		Bundle bundle = FrameworkUtil.getBundle(Test.class);
		BundleContext bundleContext = bundle.getBundleContext();
		ServiceReference<WebService> serviceReference = bundleContext.getServiceReference(WebService.class);
		WebService service = bundleContext.getService(serviceReference);
		service.setName("Foo");
	}
	
	@org.junit.Test
	@HttpTest(method=Method.GET, path="/services/hello")
	public void testServiceCall() {
		System.err.println("Test#testServiceCall()");
		assertOk(response);
		assertEquals("Hello Foo", response.getBody());
	}
}


@Path("/")
public class WebService {

	private String name = "World";
	
	@GET
	@Path("/hello")
	public String helloWorld() {
		System.err.println("WebService#helloWorld()");
		return "Hello " + name;
	}
	
	public void setName(String name) {
		this.name = name;
	}
}
```