Enhancement: Hitting and missing ships

Here we add the acceptance test for the new behaviour.

Notice we're changing the wording in the test to use more domain
specific language, talking about shooting, hitting and missing
instead of clicking. This reflects our growing understanding of the domain.
Enhancement: Hitting and missing ships

Adding a unit test for missing a ship. This spec could be refactored,
but we'll tolerate the duplication for now.
Enhancement: Hitting and missing ships

Adding the implementation to make the tests pass.