Implement unordered intrusive lazy list.

Implement unordered intrusive lazy list.

Add implementation of unordered policy for intrusive lazy list.
Implementation uses tratis::sort bool flag and std::enable_if
to choose appropriate ordered/unordered implementation of search
and equal functions.

Also this fix disables find_with function for unordered list for
simplicity. find_with is a part of public interface, so providing
alternative implementation with same name and different semantic
is arguable.