Fix tests and compiler warnings

- Added an additional check to make sure the testMessageBus doesn't refer to a different
messageBus set by previous test that also uses AbstractSinglenode test.
For instance, if RabbitSingle node tests run before
RedisSingle node tests and Rabbit wasn't available, the Redis tests still use
Rabbit message bus that was set by the AbstractSingleNode test class.
Since the TestSupportResource is evaluated after the testmessagebus
is set, adding this check is needed.

- Fixed compiler warnings
XD-1087 Create REST API for restarting a specific job instance

* Add tests
* Add rudimentary UI support

Jira: https://jira.springsource.org/browse/XD-1087
Upgrade to Spring HATEOAS 0.9
XD-1305 File Sink now supports configurable modes

Originally the file sink only supported the append mode.
Now supports APPEND, REPLACE, FAIL IGNORE
XD-1294 Update xd reactor dependency

- Move the reactor Environment bean definition out of module common context
- Remove the 'spring-xd-extension-reactor' runtime dependency from spring-xd-dirt
- Add back 'spring-xd-extension-reactor' runtime dependency to reactor-syslog module

Add reactorEnv bean to syslog module

- Add the reactor environment bean to the reactor-syslog source
module so that the reactor environment is only loaded when this
module is deployed.
XD-1316 UI:Fix E2E test warning
Update xd ui test task

 Rename ui test task to 'ui_test' so that gradle test won't
  call spring-xd-ui tests. To run the E2E tests, the ui_test
  task needs to be invoked explicitly.
 The 'ui_test' task will also build the UI and runs the unit tests
  as it depends on 'grunt_build'

 Once we have valid UI tests, we will rename the task ui_test to 'test'
  so that will run as a 'test' task.
XD-804 Added integration.support package to dirt and used in AbstractSingleNode...Tests

XD-804. Refactored SingleNodeTestSupport and SingleNodeApplication per review

XD-804 Renamed package integration.test and added module resource location support

XD-804 Updated javadocs and added moduleResourceLocation arguments to processing chain creation methods

Javadoc fixes + random ports