Eliminae unsed mixable helper
Fix mixable test
Add deprecated attribute to construcutor of mixable helper
Fix lof_storage to use mixable helper
Fix clustering/storage to use mixable helper
Fix graph_wo_index to use mixable helper
Fix recommender_mock to use mixable helper
Fix lsh_index_storage to use mixable helper
Fix inverted_index_storage to use mixable helper
Fix stat to use mixable_helper
Remove deprecated_mixable and delegating_mixable bravo!
Add deprecated attribute to functions of mixable_holder