Rotate Image

	/**
	 * You are given an n x n 2D matrix representing an image.
	 * 
	 * Rotate the image by 90 degrees (clockwise).
	 * 
	 * Follow up: Could you do this in-place?
	 * 
	 * */
	
	/*
     *   1  2  3  4
     *   5  6  7  8
     *   9  10 11 12
     *   13 14 15 16
     */