minor coding style change suggestion for the LUA core

[Benoit Germain <bgermain@...>]

Hi,

Since LUA is manipulated though the stack, watching stack position type and
contents for debugging purposes is my main activity when debugging my
extensions. I just happened to almost remember the significance of numerical
values for lua-5.0-alpha, when lua-5.0-beta came out, and swapped values
around. So I just wanted to suggest that the LUA_T<type> constants in the
lua core become enums, (and obviously the type of TObject.tt is changed to
the proper enum type), so that we can benefit from the ability of current
debuggers to display the enum entry name of a given variable instead of a
numerical value. 
Changing the code is a matter of minutes, and of course there is the issue
of the storage size, but I seem to remember that ANSI C defines enum storage
size as int as default, even if various compilers offer to override that
behaviour, so normally in the general case the storage size would not
change.

Cheers,

Benoit.