Improve log messages (#422)

- Add log messages wherever required/useful
- Remove unnecessary log messages and print statements
- Convert print statements to minetest.log
- Fix incorrect log level for some messages
- Trivial code-style fixes

mods/pvp/dropondie/init.lua

@@ -6,7 +6,7 @@ local function drop(pos, itemstack)
 
 	for _, item in pairs(blacklist_drop) do
 		if sname == item then
-			minetest.log("info", "Not dropping " .. item)
+			minetest.log("info", "[dropondie] Not dropping " .. sname)
 			return
 		end
 	end
@@ -14,13 +14,12 @@ local function drop(pos, itemstack)
 	local obj = minetest.add_item(pos, it)
 
 	if obj then
-		obj:set_velocity({x=math.random(-1,1), y=5, z=math.random(-1,1)})
+		obj:set_velocity({ x = math.random(-1, 1), y = 5, z = math.random(-1, 1) })
 
 		local remi = minetest.settings:get("remove_items")
 		if minetest.is_yes(remi) then
 			obj:remove()
 		end
-
 	end
 	return itemstack
 end