Replaces source->data_model with model, which must have the same
characteristics as source->data_model (same column types)
Also for each #GdaHolder for which source->data_model is a source model,
this method calls gda.holder.Holder.setSourceModel with model to replace
the source by the new model
Replaces source->data_model with model, which must have the same characteristics as source->data_model (same column types)
Also for each #GdaHolder for which source->data_model is a source model, this method calls gda.holder.Holder.setSourceModel with model to replace the source by the new model