Have opt-in puzzle rules and features for individual puzzles

[jkenlooper]

The owner of a puzzle should have the ability to set the puzzle rules that it will use. Related to #47 and #48 .

Some of the existing rules that could be configured are:

• hot spots
• piece stacking
• piece movement rate
• no decrease on karma when moving larger groups of pieces

Possible extra features for puzzles could be:

• Allow moving large amounts of pieces by selecting them at one time
• Invite only list that only allows the players on the list to view the puzzle
• other things?