Write up full rules set

[geoff-maddock]

Write up detailed game rules. This is in the GAME RULES file here, written using markdown. This is the comprehensive rules which will be used for play testing and from which more concise rules will eventually be written.

• Catalog of all parts, boards, cards, documents
• Description of play
• Setup of the game
• What the win conditions are
• Rules for each part of the game
  • Boards
  • Cards
  • Pawns
  • Turns of play
• Solutions to specific scenarios as they come up