Remove exploding from level
Bombers explode now, not the game
Fix bug where speed/bombs were strings
Fix a race condition

The bomber would jerk around, then get stuck stopped.

Now it appears it's not stopping and the bombs don't explode.
Added a Bomb Explosion - but ....

- I'm going to refactor to a presenter object. KaboomPresenter should
  allow the Kaboom Layer to play the animation, remove the clear and
  redraw for bombs, and finally get the explosions working.
Acceptance Test written. Try again.
Save off the diagrams
Bomber is moving again with presenter
WIP: Getting bomb updates into the presenter
Adding a game blackboard
Explosion implementation

Trying to do the explosions on the bombs when they hit.

I don't like this implementation - I started with a presenter and it
isn't working well.  In the middle I switched to a blackboard/event
based system and that's working better.

At this point when the bomb hits the explosion is off screen, the bomb
stays on screen, and then the game crashes.

Other than that it's working well :).
Don't crash on explosion.

Fixed the infinite loop when a bomb explodes.  I don't like that this
isn't tested, there's too much interaction.
Explosion in the right spot