Board checks for game over after each move
Refactoring: add place_many helper method
Start to add tests/code for minimax to score the board
Add class to get input from user
Add call to gets in get_move
Add third test and refactor

Brian and Kelly helped me with the basics of mocking/stubbing - apparently
I'm never supposed to mock the object I'm testing.  I also made a new
class to specify the IO being used so it won't always need to be the console.
Start adding output methods
Refactor and add test for ConsoleIO

I moved ConsoleIO into its own file and started adding output functions
because they don't really have anything to do with prompting the user.