GH-271: Remove duplication from pom.xml files

This proposal fixes many build warnings and is a general cleanup of the pom.xml files.

* Remove duplicate `dependency` entries  from pom.xml files
* Remove duplicate `repository` entries from pom.xml files
* Replace deprecated use of `receive(long)` in `HttpSourceTests`
* Reduce logging for Twitter integration tests

Fixes #271

function/splitter-function/pom.xml

@@ -15,12 +15,10 @@
     <description>Spring Native Function for Splitter</description>
 
     <dependencies>
-
         <dependency>
             <groupId>org.springframework.integration</groupId>
             <artifactId>spring-integration-file</artifactId>
         </dependency>
-
     </dependencies>
 
 </project>