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
Update SI Version 2.2.0 -> 2.2.6
Fix typo in Basic Mail Sample

https://jira.springsource.org/browse/INTSAMPLES-118
INTSAMPLES-119 Update Monitor for Twitter OAuth

Twitter now requires authentication.

Disable the real twitter adapter by default; enable it
with spring.profile "twitter" - requires the user to get
real oauth tokens.

Replicate oauth setup instructions from the twitter sample.

Add note to README for enabling the real twitter adapter.

Add .gitignore so committers can keep their real credentials
in, say, 'oauth.properties.foo'.

Add note about `SpringIntegrationTest`.

Update dummy tweets to use new icon.

INTSAMPLES-119 Polishing

- Fix 'twitterTemplate' bean name
- Add content to log and JMX Notification

JIRA: https://jira.springsource.org/browse/INTSAMPLES-119
Merge remote-tracking branch 'upstream/master'