Erase unneeded data when tailcalling

[Jengamon]

This should fix #53 by fill part of the stack with nil that cannot be actually used by the tailcalled function (because it does not have varargs and it was not passed in as an argument).

[Jengamon]

Nope, current "fix" breaks:

local b = {}
function b.inner(a, bk)
  print(a, bk, b == bk)
end
setmetatable(b, {
  __call = function(_, ...)
    b.inner(...)
    return b.inner(...)
  end
})

local a = b("a")

function a(b, c)
  print(b, c, b==a)
end
function d(_, ...)
  a(...)
  return a(...)
end
d("s")

let me do more digging (or it's more like it never fixed the above now that I've dug more)

[Jengamon]

this doesn't work properly so closing