sndCover now falls back to sndWatchThis OR sndFire.
sndDrat and sndBugger now fall back to each other.
foreach(dir
Art
Bamboo
Bath
Beach
Blox
Brick
Cake
Cave
Castle
Cheese
Christmas
City
Compost
CrazyMission
Deepspace
Desert
EarthRise
Eyes
Freeway
Fruit
Golf
Halloween
Hell
Hoggywood
Island
Jungle
Nature
Olympics
Planes
Sheep
Snow
Stage
Underwater
)
add_subdirectory(${dir})
endforeach(dir)