Added equals to Tuple
Added hashCode to itemSet

So I can really trust the HashMap lookup
Moved the checking of existing transformation

It makes more sense to be there. Or doesn't it? Or
does it? And why? And where?

Oh look, a squirrel!!!
Not adding the same interval twice

Just because it works with only one instance.

The more pertinent question is: why are there more of
them?? We might never know...