[Feature] Add new Spider option

[TobiasBielefeld]

From an e-mail:

Please add an option to Spider to require a card on each foundation stack before dealing a new row. That is how the Windows and other versions I've played function and although I prefer yours, I would like the option to play either way.

[zb3]

So it turns out that the original rules have this requirement, and the variant present in Simple-Solitaire is called "relaxed mode". In my fork, the original rules are the default, but the relaxed mode is available as an option.