Change lua selection floodfill and add some tests

dat/Rog-strt.lua

@@ -40,8 +40,7 @@ des.map([[
 -- Dungeon Description
 --REGION:(00,00,75,20),lit,"ordinary"
 
-local streets = selection.floodfill(selection.new(), 0,12)
-
+local streets = selection.floodfill(0,12)
 
 -- The down stairs is at one of the 4 "exits".  The others are mimics,
 -- mimicing stairwells.

dat/astral.lua

@@ -39,7 +39,7 @@ for i=1,2 do
    -- 3.6.[01]: 75% chance that both sides opened up, 25% that neither did;
    -- 3.6.2: 60% twice == 36% chance that both sides open up, 24% left side
    -- only, 24% right side only, 16% that neither side opens up
-   local hall = selection.new()
+   local hall;
    if math.random(0, 99) < 60 then
      if i == 1 then
         des.terrain(selection.area(17,14, 30,18),".")
@@ -47,14 +47,14 @@ for i=1,2 do
         -- temporarily close off the area to be filled so that it doesn't cover
         -- the entire entry area
         des.terrain(33,18, "|")
-        hall:floodfill(30,16)
+        hall = selection.floodfill(30,16)
         -- re-connect the opened wing with the rest of the map
         des.terrain(33,18, ".")
      else
         des.terrain(selection.area(44,14, 57,18),".")
         des.wallify()
         des.terrain(41,18, "|")
-        hall:floodfill(44,16)
+        hall = selection.floodfill(44,16)
         des.terrain(41,18, ".")
      end
      -- extra monsters; was [6 + 3d4] when both wings were opened up at once

dat/minetn-1.lua

@@ -115,8 +115,8 @@ des.object({ id = "magic missile", coord = place[5], buc="uncursed", spe=0 })
 
 -- the Orcish Army
 
-local inside = selection.floodfill(selection.new(), 18,8)
-local near_temple = selection.area(selection.new(), 17,8, 23,14) & inside
+local inside = selection.floodfill(18,8)
+local near_temple = selection.area(17,8, 23,14) & inside
 
 for i=1,5 + math.random(1 - 1,1*10) do
    if math.random(0, 99) < 50 then