Completed the version handling. We had to implement it as a very ugly fix, since we can't add a new 'version' column inside an 'if'-clause inside our sql script (that is caused by the HSQLDB). Added a new table containing the version. Implemented the needed SQL statements inside the ExperimentDAOImpl class. Extended the ExprimentTaskResult class and adapted the ExpriementTaskResultRowMapper class. refs issue #56
Added the creation of parent folder for cache files if they are missing. Added a JUnit test for the SingletonWikipediaApi class. refs issue #70