Corrected error in labFour_pOne things example - thanks JonathanCrawford

 *

 * @example

 * labFour_pZero_Person Jim("James");

 * Jim.setBirthday("2010-02-30"); // Jim's birthday is on February 30, 2010

 * Jim.setBirthday("2010-02-28"); // Jim's birthday is on February 28, 2010

 * labFour_pZero_Student Jane("Jane","2020-03-15");

 * Jane.setMajor(COMPUTER_ENGINEERING);

 * labFour_pZero_Instructor Gabi("Gabriella");

 *  labFour_pOne_Rectangle re1({0, 0}, 1, 2); // area 2, perimeter 6

 *  labFour_pOne_Square s1({1, 3}, 3); //area 9, perimeter 12

 *  labFour_pOne_Rhombus rh1({1, 1}, 1, 45); // area sqrt(2)/2, perimeter 4

 *  labFour_pOne_Circle({0, 0}, 1); // area pi, perimeter 2*pi

 *  labFour_pOne_Circle c1({0, 0}, 1); // area pi, perimeter 2*pi

 *

 *  vector<labFour_pOne_GeometricThing> things = {q1, re1, s1, rh1};

 *  vector<labFour_pOne_GeometricThing *> things = {&re1, &s1, &rh1, &c1};

 *

 *  labFour_pOne_GeometricThing::sumAreas(things); // returns 2+9+sqrt(2)/2+pi = 14.8487...

 *  labFour_pOne_GeometricThing::sumPerimeters(things); // returns 6+12+4+2*pi = 28.2832...