add gamble functionality. change Tortoise/Hare checkboxes to radio box

Changed the Tortoise/Hare checkboxes into radio boxes so user cannot select both Tortoise and Hare to win. When the user selects either the Tortoise or Hare radio box, the newly added Animal property:

this.picked = true;

This is one of the conditions that needs to be true in the gamble function for the user to win money if the selected animal wins.

Added an input field to display the amount of money the user has underneath the winner input field.

Lines 94 and 97 did not have a purpose so they were deleted.