Allow for multiple train/predict in one run

[rbossy]

Allow for training on multiple sets of attributions using the same embeddings and ontology.

Allow to predict on multiple sets of terms and matrices using the same embeddings and ontology.

During experiments, this feature would reduce the time since loading large embeddings is the most consuming task.

Started in branch multi-train

[rbossy]

da80f39a8109ccf38c7e7be2c1c46076d6bebdac