Some inserted bounds don't pass `validate`

This will panic during validate (assuming validate is correct):

#[test]
fn should_validate() {
    let mut t = SieveTree::<1, 2, Bounds<1>>::new();
    let a = Bounds {
        min: [5.],
        max: [10.],
    };
    let b = Bounds {
        min: [20.],
        max: [25.],
    };
    t.insert(a, a);
    t.insert(b, b);
    validate(&t);
}

element 1 origin [1500] outside of cell 8:[4] with bounds [1024]-[1279]

Ralith / sieve-tree

Some inserted bounds don't pass `validate` #9