Remove unused methods
Account for the fact that last frame may have three rolls

Previously, a frame was a vector of three elements: element 0
was the first roll, element 1 was the second, element 2 was
the cumulative total of the game after the frame.

To account for a third roll in the 10th frame, converted the
vector to a map with keys :roll-1, :roll-2, :roll-3, and
:total.
Fully functioning now, but not pretty
A big of refactoring and documentation