Check if an array contains all the entries of another array

Usage:

``
$ npm install --save array-contains-all
`

`javascript
var a = [1, 2, 3];
var b = [1, 2];
if (arrayContainsAll(a, b)) {
// Yeehaa, look ma, we did it!
}
if (arrayContainsAll(b, a)) {
// Not today sucka!!!
}
``