CLEREZZA-865: Fix serialization of bnodes for internal queries
CLEREZZA-865 Correct binding of bnodes via skolemization
CLEREZZA-865 Removed a wrong test line
CLEREZZA-865 Cleanup
CLEREZZA-866: Changed the way jdbc connections are managed. Some code cleanup to do.
CLEREZZA-865: Changed the method to preserve the mapping of bnodes in virtuoso graphs with the internal representation.
CLEREZZA-865: Re-enstablished bidimap for bnodes in input
Merge commit '0a3c1ddf72c2bc419c5cc6fff7d63c33b6a71c13'

* commit '0a3c1ddf72c2bc419c5cc6fff7d63c33b6a71c13':
  CLEREZZA-865: Re-enstablished bidimap for bnodes in input
  CLEREZZA-865: Changed the method to preserve the mapping of bnodes in virtuoso graphs with the internal representation.
  CLEREZZA-866: Changed the way jdbc connections are managed. Some code cleanup to do.
  CLEREZZA-865 Cleanup
  CLEREZZA-865 Removed a wrong test line
  CLEREZZA-865 Correct binding of bnodes via skolemization
  CLEREZZA-865: Fix serialization of bnodes for internal queries