Change minetest.after() to a function that is called on next globalstep in redstone...

...for more speed and stability(since minetest.after uses table.remove, which is much less efficient because we can handle all elements at once since it is the next globalstep and not more. We get a time of O(n) instead of O(n^2) if n is the number of functions that will be called this globalstep)