[luatex] convention for lua packages and file names

[Arthur Reutenauer]

> The .lua file registers a module called 'metapost'. I think the convention 
> should be to call the file 'metapost.lua', to have a parallel with LaTeX: 
> like foo.sty provides the package foo, bar.lua should provide the module 
> bar.

  Sounds good to me, but I'm afraid it won't fit in every situation;
think of pstricks with its dozens of pst-* subpackages: in those cases,
it's probably nicer to store those modules in subtables; but then you
would have a file called foo.bar.lua which is a bit awkward (although
possible on modern filesystems).

> When the package is for LuaTeX only, should it have a prefix in its name? 

  I don't think so.  Unless LaTeX starts some sort of internal fork
between LuaTeX and other engines, but that doesn't seem likely for the
moment.

> In the case of a package that is adapted to LuaTeX, like inputenc for 
> example, I think it should be names luainputenc (not lua-inputenc).

  To match with xe* packages?  Sure, why not.  But it's probably not the
best idea to rename lua-inputenc to luainputenc now.

	Arthur