tuned comments;
modified signature to return string, instead of relying on side-effect;
moved list-based implementation to its own module;
fixed dependency order;
renamed 'db' to 'empty' to clarify its value;
added init function;
updated structure based on signature change;
updated first test to use Moana_lists module, rather than Config;
Resolved the conflict in tests.ml

Merge branch 'master' of https://github.com/niksu/MoanaML into niksu-master

Conflicts:
	tests.ml
Merge branch 'niksu-master'