Fixes#2550 by adding a check for space turf at the location of the mob
before playing a bodyfall sound
Fixes#2494 by following Carn's suggestion of determining whether a hat
will fall off based on its head cover and head hide flags.
Thank you @Razharas and @MrPerson for help with bitflags.
Thanks @Supersayu for providing a lot of this code.
560c5fc781