Perform a set difference A-B by subtracting all items in array B from array A.

@param {Array} arrayA
@param {Array} arrayB
@return {Array} difference
function(arrayA, arrayB) {
            var clone = slice.call(arrayA),
                ln = clone.length,
                i, j, lnB;

            for (i = 0,lnB = arrayB.length; i < lnB; i++) {
                for (j = 0; j < ln; j++) {
                    if (clone[j] === arrayB[i]) {
                        erase(clone, j, 1);
                        j--;
                        ln--;
                    }
                }
            }

            return clone;
        }