Take Synonyms and Relations into account

Issue Summary

I would really like to see this module take taxonomy terms Synonyms and Relations into account.
For instance, if I have defined Horror and Survival Horror as Synonyms or Related, Horror and Survival Horror Nodes are shown as relevant for another Horror node.
Maybe you can even add some other kind of feature with Relations, for example, making Related taxonomy terms appear first.

Thanks again for this great module. :)