Add drop shadow support when using hand

[fletcher]

When using the hand functionality, if the the cards have a mostly uniform background color, they all blend into each other when fanned out. For example, a custom set of playing cards with a white background loses any differentiation between the cards where they overlap.

From what I can tell the drop shadow functionality only works for save_png, not for hand. It would be great if that could be added to hand as well!! (If there is a way to do this already that I missed, my apologies!!)

Either way, thank you for a great project!! I've experimented with several projects for quick home built play testing, and printed one deck with MakePlayingCards.com with fantastic results!!

[andymeneely]

Should be pretty easy - I'll see what I can do!