This class can broup bidimensional arrays by a given element.
It can take as parameter an array that contains a set of arrays with element values.
The class sorts the array grouping it by the elements of the set of arrays in a given positions similar to SQL GROUP BY clause.
Multiple elements may be used to group the array.
The class returns an array with the grouped elements containing two values: the first with the grouping key values and another with an array with remaining values.