LR-99: Battle Engine v1

Update monsterAttackPhase() so that it returns True if the battle should continue and False if the battle should end. 

The code would follow a path like this:

* mosterAttackPhase() do the check to see if the player is dead
* If the player would have died, monsterAttackPhase() can (a) restore some of the Player's health and (b) return a boolean value indicating that the battle has ended
* battle() method checks to see if monsterAttackPhase() has indicated that a 'Gandolf save' took place. If it did, it will end the battle *and* make a note that the final battle phase (where player is awarded experience / items) should be *skipped*.