[Examples] Fix Inverted Arrow & Diamond Arrow

[discoleo]

Examples: Inverted Arrow & Diamond Arrow

• should have been already fixed;
• the code is in function all_arrows, lines 182 - 196;
• value of d = -0.5 for Inverted ArrowHead;
• d.head currently requires 2 values for the proper diamond (this may change);

  # Inverted ArrowHead
  x = c(3, 3);
  d = -0.5;
  d.head=c(-0.5,0.5)
  a3 = arrowInverted(x, y, d=d, d.head=d.head, lwd=2);
  text(3, yt,
       "Inverted", cex = 0.75);

  # Diamond ArrowHead
  x = c(5, 5);
  d.head = c(-0.5, 0.5);
  d = -0.5;
  arrowDiamond(x, y, d=d, d.head=d.head, lwd=2, join=0);
  text(5, yt,
       "Diamond", cex = 0.75);

[DarianFlorianVoda]

Added