INTSAMPLES-137: Add WebSockets sample

JIRA: https://jira.spring.io/browse/INTSAMPLES-137

Depends on https://github.com/spring-projects/spring-integration/pull/1274

Polishing and cleanup

* Fix `cafe-dsl` project: https://build.spring.io/browse/INTSAMPLES-NIGHTLY-JOB1-1131
* Change author emails to the `pivotal.io`
* Regenerate poms

Fix for `Cafe-DSL` sample

https://build.spring.io/browse/INTSAMPLES-NIGHTLY-JOB1-1143

basic/web-sockets/README.md

@@ -0,0 +1,29 @@
+WebSockets Sample
+==============
+
+This example demonstrates the Standard WebSocket protocol (without any sub-protocols) with Spring Integration Adapters.
+It just sends current time from the server to all connected clients.
+
+## Server
+
+The server is presented only with a single `org.springframework.integration.samples.websocket.standard.server.Application`
+class, which is based on the Spring Boot AutoConfiguration and Spring Integration Java & Annotation configuration.
+It is a `main` and starts an embedded Tomcat server on the default `8080` port. The WebSocket endpoint is mapped to the `/time` path.
+
+The server also can be run from Gradle `gradlew :web-sockets:run`
+
+## Java Client
+
+The `org.springframework.integration.samples.websocket.standard.client.Application` is a simple Java application,
+ which starts an integration flow (`client-context.xml`), connects to the WebSocket server and prints `Message`s to the 
+ logs, which are received over WebSocket.
+   
+## Browser Client
+   
+The `index.html` in the `src/main/resources/static` directory of this project demonstrates a JavaScript `SockJS` client, which connects
+to our server and just prints its messages in the middle of page.
+ 
+## Test Case
+
+The `org.springframework.integration.samples.websocket.standard.ApplicationTests` demonstrates the Spring Boot test 
+framework and starts Server & Client to check, that the client receives correct data.