optimize _.intersection for performance

`_.intersection` can be faster if the smallest set is passed to the `_.filter` instead of the first one.

We can do this because of `commutative property` of sets:
A ∩ B = B ∩ A

jsPerfs:
[small set[3] as the first passed set](http://jsperf.com/improve-intersection/9)
[medium set[10] as the first passed set](http://jsperf.com/improve-intersection/8)
[large set[100] as the first passed set] (http://jsperf.com/improve-intersection/10)