CDAP-471

1) In standalone, now stops all components, if one fails. JIRA issue has been opened to restart runnables if they fail: https://issues.cask.co/browse/CDAP-477
2) Validate the handlers that user passes in during deploy time
3) Move construction of NettyHttpServer to constructor of ServiceHttpServer (from startup)
4) Add a small test case to test (2)

https://bamboo-prod.continuuity.com/browse/CDAP-DUT79
Oh. missed that. Although usually the method javadoc don't say about implementation. E.g. in future, the verification can be done by some other means (may not be even using NettyHttpService).