Vowel families
Given two words, we can determine if they have the same vowels, ignoring order and repetition. For instance, "Hello" and "Vowel" both have \e and \o, so they have the same vowels. Write a function that groups words into "families" that all have the same vowels. "Tree" and "tent" also belong to the same family because we ignore the repetition of \e.
Examples
(vowel-families ["hello" "vowel" "fox" "cot" "hat" "cat"]) ;=> [["hello" "vowel"]
; ["fox" "cot"]
; ["hat" "cat"]]
