_areAllUnique = function (src) {
		if (src.length < 2) {
			return true;
		}

		var sorted = src.slice().sort();
		var last = sorted[0];

		for (var i = 1, ien = sorted.length; i < ien; i++) {
			if (sorted[i] === last) {
				return false;
			}

			last = sorted[i];
		}

		return true;
	}
Determine if all values in the array are unique. This means we can short
cut the _unique method at the cost of a single loop. A sorted array is used
to easily check the values.

@param  {array} src Source array
@return {boolean} true if all unique, false otherwise
@ignore