Add snow to excavation. No treasures will drop from snow by default,

but they can be added to the treasures.yml file by specifying

"Drops_From:
	Snow: true"

Adds #1229

src/main/resources/config.yml

@@ -313,6 +313,8 @@ Experience:
         Gravel: 40
         Mycel: 40
         Sand: 40
+        Snow: 20
+        Snow_Block: 40
         Soul_Sand: 40
     Woodcutting:
         Oak: 70