Unused fields in DomainLookupTree and Node.

[Brian3647]

DomainLookupTree has a field named minimum_level and Node has a field named data.
None of this fields are used anywhere. And they are private fields.

What are they for?

[Phineas]

minimum_level is something I was going to implement later on which let you set a minimum domain level for lookups, so insertions would always be clustered and inserted by their minimum level which minimizes the traversal iterations if you always look up by at least a minimum level of domain. E.g. if minimum level was 1, then inserting www.google.com would insert google.com into the root of the tree, and so on. Will likely implement it soon.

data is stored in each node for visibility & debugging purposes, or if someone's directly using the traverse function and wants to identify the node they've hit.