Ninjas can now kill you, read description

-Added playerRespawn() which spawns the player back to the start at 8,0 on the grid and erases previous player position
-Added gameOverCheck(), method runs before you make your next input to move in UserInterface. And no buttholes have been ripped. If lives < 0 then "Game Over" will print and close the program
-Added killCheck() that takes a ninja's current position and checks the four directions if player's position is there. If player position is true, then you die then respawn. This method gets called before a ninja moves; they can't kill you after they have made their move.

These changes will not break the program, I have tested this before updating

Current Issues:
-Ninjas can sometimes multi kill you causing your lives to go from 3 to some random number thats not 2
-Issue where you can move into ninja position causing them to not be able to kill you, unless you move into kill range