Matrix3x2d.rotate

Apply a rotation transformation to this matrix by rotating the given amount of radians. <p> If <code>M</code> is <code>this</code> matrix and <code>R</code> the rotation matrix, then the new matrix will be <code>M * R</code>. So when transforming a vector <code>v</code> with the new matrix by using <code>M * R * v</code> , the rotation will be applied first!

@param ang the angle in radians @return this