Add HadoopFileSystemTestSupport Rule

- Update: Add getter for configuration

Use retries = 1
XD-1251 Allow config of Access-Control-Allow-Origin

Use can set the value xd.ui.allow_origin to override the
default (http://localhost:9889).
XD-1251: Assume use of HttpClient for twitterstream

The existing DirectFieldAccessor workaround for setting connection
properties assumed the use of a SimpleClientHttpRequestFactory. If
Apache HttpClient is on the classpath, a different instance is
dynamically chosen. This commit adds httpclient explicitly and fixes
TwitterStreamChannelAdapter to work with the different request factory.