Zepto#find(somethingFalsey) should return $()

Now, `Zepto#find(somethingFalsey)` return a pure empty array.
But `Zepto#find(somethingFalsey)` should return a `$()`.

Because:
 * We expect `Zepto#find` to return collection
 * jQuery compatibility (for v1.11.1 and v2.1.1)