Add debug + fix subgroup naming in 'write'.
Added basic file creation example (currently showing bug in 'complete').
Improved readability for test groups in test_complete.
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).