Added Ti-SRS and modified delay curve behaviour on Marathon 2020.

I realized that playing at 4/8 for 800 levels straight is probably too much,
so I made it that only the first 10 sections count for advancing the delay
curve faster than it would normally go. Now only the last 500 levels can be
at delay level 20.

tetris/rulesets/standard_ti.lua

@@ -0,0 +1,30 @@
+local Standard = require 'tetris.rulesets.standard'
+
+local SRS = Standard:extend()
+
+SRS.name = "Ti-SRS"
+SRS.hash = "StandardTI"
+
+function SRS:onPieceMove(piece, grid)
+	piece.lock_delay = 0 -- move reset
+	if piece:isDropBlocked(grid) then
+		piece.move_counter = piece.move_counter + 1
+		if piece.move_counter >= 10 then
+			piece.locked = true
+		end
+	end
+end
+
+function SRS:onPieceRotate(piece, grid)
+	piece.lock_delay = 0 -- rotate reset
+	if piece:isDropBlocked(grid) then
+		piece.rotate_counter = piece.rotate_counter + 1
+		if piece.rotate_counter >= 8 then
+			piece.locked = true
+		end
+	end
+end
+
+function SRS:get180RotationValue() return config["reverse_rotate"] and 1 or 3 end
+
+return SRS