Smarter handling of click capture in graphical dice

[cwegrzyn]

As discussed in #495, the default behavior for the dice is to block clicks. This is done to avoid surprising behavior, especially since on mobile, the dice can block lots of the screen.

PR #509 adds some options that let people opt in to ways to make the dice less intrusive. But ideally we could make click through a default behavior.

Two things that would make it feel safer:

1. The dice themselves should still capture clicks. (But at the time of writing dice box doesn't have support for detecting clicks to dice)
2. Possibly limit the scope of what clicks are allowed-- for example, if we show a modal after a roll, only clicks inside the modal should work. In particular, clicking outside the modal shouldn't close the modal-- you are probably just clicking to remove the dice!