Various refactoring and renaming:

 - renamed packages to distinguish index-related classes from search tests
 - use JacksonProvider for jsonpath parsing (provides a small speedup). Note:
   this does change the output slightly as it passes-through invalid multi-byte
   characters instead of removing them. This behaviour is consistent with the
   JSON encoding characteristics of the backend however.
 - add log4j config and use logger for error and debug messages
 - refactor MultiSource so it calls finish() on its composed sources as they
   as iterated. The seems to fix the resource exhaustion bug that emerged with
   large datasets.