special case strip(call_move) to stripmove()

this gets called so much the extra function overhead actually seems bad

vacuum_gambit.p8

@@ -107,6 +107,22 @@ function linked_list:strip(f)
  self.tail = p
 end
 
+-- stripmove calls x:move() for
+-- each node, removing each node
+-- for which x:move() is true.
+function linked_list:stripmove()
+ local p, n = self, self.next
+ while n do
+  if n:move() then
+   p.next = n.next
+  else
+   p = n
+  end
+  n = n.next
+ end
+ self.tail = p
+end
+
 -- optimized special case -
 -- could be done with strip but
 -- this avoids extra function
@@ -185,14 +201,6 @@ function _update60()
  mode:update()
 end
 
-function call_f(x)
- return x:f()
-end
-
-function call_move(x)
- return x:move()
-end
-
 function ones(n)
  local ret = 0
  while n != 0 do
@@ -233,9 +241,8 @@ function updategame()
   current_wave:load(0, 0, min(ones(waves_complete)\2, 4))
  end
  events:vore(new_events)
- events:strip(call_move)
- for _, lst in ipairs{intangibles_bg, eships} do
-  lst:strip(call_move)
+ for _, lst in ipairs{events, intangibles_bg, eships} do
+  lst:stripmove()
  end
 
 	-- eship collider will be used
@@ -257,7 +264,7 @@ function updategame()
    return eb:hitship(ps)
   end)
  else
-  ebullets:strip(call_move)
+  ebullets:stripmove()
  end
 
  pbullets:strip(function(pb)
@@ -268,7 +275,7 @@ function updategame()
   end
  end)
  
- intangibles_fg:strip(call_move)
+ intangibles_fg:stripmove()
 
 	if waves_complete == 32767 and not eships.next and not ebullets.next and not events.next then
 	  game_state = win