improve priority in clusters - suffix score

[StorkST]

Today formed group:
видеться/у-
обижать/обидеть
предвидеть

But we want:
видеться/у-
предвидеть
обижать/обидеть

Solution:

• either this can be fixed by not recognizing the relation and exclude обижать/обидеть (see comment TODO in the first case in the compare function)
• either have 2 relations: a Relation.STEM for видеться/у- and предвидеть, and a new Relation.lowerSTEM for обижать/обидеть and предвидеть