Remove obsolete query._clone() method which did shallow copy of query object
Micro optimization
Remove unused translator.inside_order_by flag
Distinct optimization
Set attribute cannot be used for ordering
Refactoring: move order_by_numbers() and order_by_attrs() methods from query to translator
Query can be built step-by-step using .filter() method: q = select(...); q.filter(...); q.filter(...)
Merge master to orm: query can be built step-by-step using .filter() method