Overlord - Iteration 3

In this iteration, I made the following changes based on the review in Iteration 2:

1. DRYed out the `if bomb.incorrect_deactivation_attempts == 3` in `overlord.rb`

2. Made use of layouts to DRY out my views

3. Added additional edge cases and labeled features happy, sad and bad.

I chose not to use a hash of parameters in initializing a bomb. I felt passing in two keyword arguments for the activation and deactivation codes are sufficient as the other two bomb attributes, `status` and `incorrect_deactivation_attempts` should never change from bomb to bomb. However, I do understand the benefits of passing in a `bomb_params` method that permits specified parameters, as we would in a Rail's controller.

Thanks!