Rotate Matrix: Write a function named rotateMatrix() that takes a rectangular array of numbers (a matrix) and returns the matrix rotated 90 degrees to the right.
Input: [ [29, 62, 8], [12, 60, 31], [99, 79, 12] ];
Output: [ [99, 12, 29], [79, 60, 62], [12, 31, 8] ];