* Remove `MessageChannel` beans whenever their really don't need to be exposed into the target application context.
Use local property definition instead in the configuration class
* Make Twitter `Consumer` configurations conditional on their required properties
to avoid auto-configuration for those bean which are not going to be used in the target application
* Fix all the Checkstyle violation in the effected modules
* Fix Twitter modules READMEs to reflect a nature of the auto-configuration
* Add (and mention in README) new `enabled` properties for various Twitter supplier configurations:
by default all of them would be started just by the presence in classpath
* Add `spring-` prefix to function names
Fixes: #9
This commit renames each sub-module in the common, consumer, function
and supplier groups with a prefix of `spring-`.
* Update README.adoc links to new prefixed names
