End of Unit 4: Yahtzee Project

Purpose: to create a two player text based game.
# 1. Complete the code -alone- using the template below.
# 2. Do not 're-write' the project, make use of it.
# 3. Rules of the Game: https://en.wikipedia.org/wiki/Yahtzee
#    A sample graphical game example to play: https://cardgames.io/yahtzee/
# 4. Two Human players play a game of Yahtzee together 
# 5. The game ends when both players fill their score sheet
# 6. A turn consists of one, two or three dice rolls.
#    A turn ends when (a) a player makes the third roll and scores
#    or (b) when a player stops rolling to record the dice on the score sheet.
#    The score-sheet consists of 13 slots.  Follow the rules for
#    filling in the score sheet.  
# 7. Note: you must create a Command Line Interface for your game
# 8. commands must include:
#    sheet - displaying a player's full score sheet
#    score (1-13) - selecting a spot to score the current dice
#    rollDice() - rolling all free dice
#    displayDice() - showing the player their current dice.
#    holdDie (1-5) - a method of holding / keeping dice not to be rolled
#    releaseDie(1-5) - a method of releasing dice so they can be rolled.
#    help() - prints out a list of all valid commands for your CLI 
# 9. Follow the Major Programming Rubric - Keep a Journal!
# 0. REMOVE TEMPLATE INSTRUCTIONS - REPLACE WITH YOUR COMMENTS
#