Add seeds for repeatable deck orders

[karthik-shanmugam]

Feature Description:

• Games now contain a seed, which are used to shuffle the deck
  • Enables different users to play the same deck order and compare times
• The url fragment is used to display and set the current seed
  • If the fragment is set and doesn't match the currently saved game, loading will fail and a new game will start with the new seed
  • Model.restart will generate a new seed and display it as the fragment

Possibly fulfills #16 (I didn't even notice this issue before implementing this lol)