Re-factored.

Added score update and delay setting functions.
Added arrow to show where to look.
Crib is now collected when the cards are discarded :-)
Fixed the bug in temporary computer card selection.
Re-factored massively.

All the constants have been broken out to CribbageGame::Constants in constants.rb.
The play to 31 has been broken out to a Player31 class in player31.rb.
Added set_phase().
Added set_arrow()