Better way of working out if any enemies are alive
Separate engine logic into playerTurn() and enemyTurn()
Call engine::start() from engine::play() instead of main()
Bug fix: quit wouldn't quit

Added engine::running to keep track of whether or not we should quit.
Still needs work!
Better num_dice_rolls parameter (60 is too much)
Merge branch 'engine'

* engine:
  Bug fix: quit wouldn't quit
  Call engine::start() from engine::play() instead of main()
  Separate engine logic into playerTurn() and enemyTurn()
  Better way of working out if any enemies are alive

Conflicts:
	src/engine.c++
	src/engine.h++
	src/ring.c++