[ANN] my libraries updated for 5.1

[Luiz Henrique de Figueiredo <lhf@...>]

I've updated my libraries to Lua 5.1. See
	http://www.tecgraf.puc-rio.br/~lhf/ftp/lua/

Only minor changes have been made; there are a few points that the API
in 5.1 allows shorter and cleaner code. I've also fixed a bug in most
libraries: the value returned by luaopen_* was wrong and so unusable as
the value returned by require.

(I've still to update lpdf but I have to see whether it's worth upgrading
it to support the newer versions of PDFlib.)

All feedback welcome. Enjoy.
--lhf