INTSAMPLES-114 Twitter Search Requires Authentication

* Update Sample to Spring Integration 2.2.4
* In the sample - disallow unauthenticated Twitter Searches
  - As of Twitter API version 1.1, users must be authenticated to perform searches.

For reference see: https://jira.springsource.org/browse/INTSAMPLES-114
Merge pull request #93 from ghillert/INTSAMPLES-114

INTSAMPLES-114 Twitter Search Requires Authentication