(change:major) Refactored build.xml so that thirdparty classes are stored inside workload jars that use them and not inside the main RAIN jar. This is done to avoid binary conflicts between different versions of a class (e.g., the RUBiS workload failed to run - not to compile - since the RAIN jar contained two versions of the Apache HTTP Components: the ver. 4.2.3, coming from thirdparty/httpcomponents-client-4.2.3 and an older version stored inside the thirdparty/riak-java-client/target/riak-client-1.0.6-SNAPSHOT-jar-with-dependencies.jar, which is a jar file only used by the RIAK workload.