As a bowler, I want to separate my throws into "frames" consisting of two throws

[agartee]

From the spec document:

Each game, or “line” of bowling, includes ten turns, or “frames” for the bowler. In each frame, the bowler gets up to two tries to knock down all the pins. If in two tries, he fails to knock them all down, his score for that frame is the total number of pins knocked down in his two tries.

• [x] frame implementation
• [x] two tries per frame
• [x] calculate total # of pins knocked down for the frame
• [x] valid combinations restrictions
  • Invalid Example. 5 pins in first try, 6 pins in try two
  • valid ex. 5 pins try one, 5 pins try two

[agartee]

Note that a bowling game always has exactly 10 frames. Do with that what you will =)