Automatic stub registration (#64)

before this change the support for Stub Runner Boot with Service Discovery was pretty useless since Stub Runner stubbed service discovery. That makes a lot of sense in unit / integration tests but not when you want to do some version of end to end tests. 

With this change you can pass a property to enable automated registration of stubs in Service Discovery.

Technical changes:
* Added Zookeeper registration
* Added Eureka registration
* Added Consul registration
* Added checkstyle plugin - fixed part of exceptions

tests/spring-cloud-contract-stub-runner-boot-eureka/src/test/resources/logback.xml

@@ -0,0 +1,25 @@
+<!--
+  ~  Copyright 2013-2016 the original author or authors.
+  ~
+  ~  Licensed under the Apache License, Version 2.0 (the "License");
+  ~  you may not use this file except in compliance with the License.
+  ~  You may obtain a copy of the License at
+  ~
+  ~       http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~  Unless required by applicable law or agreed to in writing, software
+  ~  distributed under the License is distributed on an "AS IS" BASIS,
+  ~  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~  See the License for the specific language governing permissions and
+  ~  limitations under the License.
+  -->
+
+<configuration>
+
+	<include resource="org/springframework/boot/logging/logback/base.xml"/>
+	<logger name="org.springframework.cloud" level="DEBUG"/>
+
+	<root level="INFO">
+		<appender-ref ref="CONSOLE" />
+	</root>
+</configuration>