Updated for 0.8.6 (still works for 0.7.x)

All functions appear to work reliably on both versions, except for a couple of very intermittent flakes only on Dancing Lights:

• in 0.8.x only, I once got things into a state where setting a token document flag to "Dancing Lights"wasn't "taking" - so it never attempted the deletion. Meanwhile setting this flag was working flawlessly for other tokens - weird! They can still be removed manually, of course.
• In 0.7.x only, I encountered a situation where the GM deleted the lights but they only went away for the GM. As I logged other players in, everyone else could still see them. The GM needed to log out and log back in to delete them manually.

These issues don't happen at all consistently, making them difficult to reproduce, and I think the module as a whole is in better shape than it was - plus all the functions are working in 0.8.