fix bufistype hopefully...

src/main.lua

@@ -75,7 +75,11 @@ local function load(name)
     return content["buf"],content["dimensions"]
 end
 local function bufistype(buf, x,y,z, targettype)
-    return buf[posasstring(x,y,z)] == targettype or (targettype == 0 and buf[posasstring(x,y,z)] == nil)
+    if targettype == 0 then
+        return (buf[posasstring(x,y,z)] == 0) or (buf[posasstring(x,y,z)] == nil)
+    else
+        return buf[posasstring(x,y,z)] == targettype
+    end
 end
 local function fill_getneighbors(x,y,z, sx,sz, seltype,buf)
     local out = {}