add sneak_glitch mod

sneak_glitch/README.txt

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+ Minetest mod: sneak_glitch
+============================
+This mod re-enables the sneak glitch in your Minetest world. It
+will allow you to use the 1-row and 2-row sneak ladders again.
+
+
+License: CC0
+Dependencies: (none)
+
+
+ Old sneak behaviour
+----------------------
+If you dislike the new sneak code, add the following setting
+to your minetest.conf file:
+
+  sneak_glitch.use_old_code = true
+
+In case you used the ingame command `/set` to do this change,
+rejoin the world in order to apply the new settings for this mod.
+
+
+ Other climbing mods
+---------------------
+Make all leaves climbable [climbing_leaves]
+	https://forum.minetest.net/viewtopic.php?t=15679
+	https://github.com/pithydon/climbing_leaves
+
+Mountain Climbing [handholds]
+	https://forum.minetest.net/viewtopic.php?t=17069
+	https://github.com/Ezhh/handholds

sneak_glitch/init.lua

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+-- Enable the sneak glitch (horray!)
+
+local use_old_code = minetest.settings:get_bool("sneak_glitch.use_old_code")
+if use_old_code == nil then
+	-- Default to the new sneak code
+	use_old_code = false
+end
+
+minetest.register_on_joinplayer(function(player)
+	player:set_physics_override({
+		sneak_glitch = true,
+		sneak = true,
+		new_move = not use_old_code
+	})
+end)

sneak_glitch/settingtypes.txt

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+#    Replaces the new sneak behaviour with the old one
+sneak_glitch.use_old_code (Use old sneak code) bool false