Add Variable search to grouping.find_named_definition.
Fix dim-length inference in complete. Enhanced test_complete.
Fix+test problems identifying and adding missing dims in subgroups.
Start containers example -- not yet working.
Reorganised and begun test -- not working, possible bug in core?
Simple containers tests working.
Test for semantic_containers.eg_simple_flat/grouped -- working.
Containers scheme comments+ideas added.
Enhanced containers code ideas -- not yet tested.
Tiny error fixes in new ideas (still untested).
Revert temporary fix to eg_allinfo.