Rename functions and remove unwanted recursion

I did some small changes that you might like to have a too! 

* README.md refers to getHypernyms and getHypernymsTree, so i changed this accordingly. It makes sense since some words have multiple hypernyms "dog" for instance has both *canid* and *domestic animal*

* getHyponyms for some reason recurs through the whole tree if I understood it right. This is superheavy if you for instance need to have hyponyms abstract word such as *entity*.

Awesome tool! I like it alot :D