returns the that player 1 has won on the first row
ends game if players win in any space
added tests to ensure that it-there-a-winner returns true for all possible winning lines)
changed is-there-a-winner to winner? and check-game-statue to game-over? also refacted winner?
checks if X's or O's win, and responds appropriately
can verify if it is a valid move - still need to deal with the case if the user puts in a character that cannot be coerced into an Integer
handles inputs that aren't numbers by continuing to prompty user for a move
extracted out rules, utility, and game classes
added tests
added tests to core
Merge pull request #2 from elizabethengelman/human-vs-human

Human vs human