Added an experimental routine to serialize the CompositeSourceModel
Added an experimental routine to serialize the CompositeSourceModel


Former-commit-id: a6fe8ddedd02b689f1a2e451c6cea0401cca378e [formerly a6fe8ddedd02b689f1a2e451c6cea0401cca378e [formerly 5e8e5eceec3f0efbb43f866ee6f1672006fed099]]
Former-commit-id: a9b6b5202b0822d593d941209064b5233d3e82f2
Former-commit-id: 4b8456a650a3369a425b4f63ba755493d45dddf0
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine