[tex-live] TL'18: LuaTeX and Lua version

[Akira Kakuto]

Hi Norbert,

> That is not easily possible, but what is possible is
> that we add formats for the luatex53.

In order to use luatex53 as a TeX engine, with the
other luatex on lua-5.2, a little more change is needed.
I asked developers what is their plan.
They asked that luatex53 is not intended to use as above.
It is provided only for tests of lua-5.3 scripts.

If you discard luatex on lua-5.2, then it is possible to
use the present luatex53 as a TeX engine.
You have to rename it as luatex.

In W32TeX, luatex on lua-5.3, with format files, is provided
for tests and for ConTeXt:
luatex-exp-w32.tar.xz
luatex-exp-w64.tar.xz

Best,
Akira