Several performance improvements in predictions

- Forcing garbage collection in ensembles' batch predictions
- Reducing bandwidth checking resources creation
- Reducing processing in input data dict construction
Bug fixing batch predictions format and memory improvements

- Fixing bug: batch predictions did not include confidence when
  --prediction-info full was used.
- Improving single model local predictions performance.
- Forcing garbage collection to lower the memory usage in ensemble's
  predictions.
Fixing bug: predictions for --no-test-header flag failed
Removing debug trace leftover in tests