better letter choice for hashing

Locations.hs

@@ -162,8 +162,8 @@ display_32bits_as_dir :: Word32 -> String
 display_32bits_as_dir w = trim $ swap_pairs cs
 	where 
 		-- Need 32 characters to use. To avoid inaverdently making
-		-- a real word, use the alphabet without vowels.
-		chars = ['0'..'9'] ++ "bcdfghjklnmpqrstvwxyzZ"
+		-- a real word, use letters that appear less frequently.
+		chars = ['0'..'9'] ++ "zqjxkmvwgpfZQJXKMVWGPF"
 		cs = map (\x -> getc $ (shiftR w (6*x)) .&. 31) [0..7]
 		getc n = chars !! (fromIntegral n)
 		swap_pairs (x1:x2:xs) = x2:x1:swap_pairs xs