Compatibility with Lua 5.X

[Tomas Guisasola Gorham <tomas@...>]

	Hi

	Recently I've experimented adapting code of some libraries to
work with all Lua 5.X versions and it was much less work than I expected.
I hadn't tried to do the same with applications.
	The initial goal was similar to that of Compat-5.1
(http://www.keplerproject.org/compat), but after adapting StringDistance,
LuaExpat and LuaSQL Postgres driver, I realised the changes do not deserve
a set of files as Compat-5.1 provided.	First, because the changes are
minimal (at least in these cases, where there is no use of environments).
Second, because there are changes that need manual correction.
	I presume changing the modules to work just like Lua 5.2 will also
work for Lua 5.0 and for Lua 5.1, except that the global variable with
the module won't be created anymore.  This is a small incompatibility
I think it pays its way.  Anyway, I think this would be a good change
for all simple cases; the complex ones could be treated separatelly.
	If anyone is interested, I have just opened a page to register
the experience at:

http://lua-users.org/wiki/CompatibilityWithLuaFive

	Any suggestion will be welcome.

	Regards,
		Tomás