Fixed randomisers in A1-A4 modes:

- History 4-rolls, history 6-rolls and history 6-rolls 35-bag no longer deal S, Z or O as their first piece
- Added a 7-bag randomiser with the same behaviour (bag7noSZOstart)
- Tweaked the "35-bag" part of the history 6-rolls 35-bag randomiser to work closer to what it's supposed to be
- Switched Marathon AX4's randomiser from history 6-rolls to 7-bag no SZO start

tetris/randomizers/history_6rolls.lua

@@ -4,16 +4,22 @@ local History6RollsRandomizer = Randomizer:extend()
 
 function History6RollsRandomizer:initialize()
 	self.history = {"Z", "S", "Z", "S"}
+    self.first = true
 end
 
 function History6RollsRandomizer:generatePiece()
-	local shapes = {"I", "J", "L", "O", "S", "T", "Z"}
-	for i = 1, 6 do
-		local x = math.random(7)
-		if not inHistory(shapes[x], self.history) or i == 6 then
-			return self:updateHistory(shapes[x])
-		end
-	end
+    if self.first then
+        self.first = false
+        return self:updateHistory(({"L", "J", "I", "T"})[math.random(4)])
+    else
+        local shapes = {"I", "J", "L", "O", "S", "T", "Z"}
+        for i = 1, 6 do
+            local x = math.random(7)
+            if not inHistory(shapes[x], self.history) or i == 6 then
+                return self:updateHistory(shapes[x])
+            end
+        end
+    end
 end
 
 function History6RollsRandomizer:updateHistory(shape)