Updated code, updated javadoc, added some functionnalities

- Added the ability for the player to create hsi own boats
- The program asks the user if he wants to create his boats himself, or
if he lets the computer handle it for him
- Added a method to know if the boat sunk after the last action
- When a boat is sunk, the player is now informed
- The 5 boats are called by their names on the console
- The player now chooses where he wants to shoot
  -> only player2 still plays randomly