Clean up importSource after flattening a model
Clean up importSource after flattening a model

hsorby/libcellml,nickerso/libcellml,nickerso/libcellml,nickerso/libcellml,cellml/libcellml,cellml/libcellml,hsorby/libcellml,cellml/libcellml,hsorby/libcellml,cellml/libcellml,nickerso/libcellml,hsorby/libcellml