Memory consumption for tables

[Mark Hamburg <mhamburg@...>]

In the following ancient message:

http://lua-users.org/lists/lua-l/2003-09/msg00066.html

I outlined how to reduce memory consumption for tables by repacking the
value and key.

This contains one nasty bug as it turns out. One cannot use lu_byte for the
type code because that value is unsigned and LUA_TNONE is -1. Using a signed
char for the type codes does, however, work.

Mark