deprecating 'for x in t'

[Lucas Ackerman <glitch@...>]

>> How deprecated is the 'implicit pairs()' case anyways?  I'm using it
>> throughout - should I change my habits?  0:)
>
>Yes. There is a good chance of it not being present in 5.1 final.
>
>-- Roberto

I would like to see this resolved as well.  Either officially kill it, 
give a compiler option to dissallow it (probably not good to fragment the 
language base), or make it syntactic sugar for 'for x in pairs(t)', so 
that it always goes through the pairs function.  The latter option is my 
preference, as it allows us to override the default table iteration in a 
clean way, short of the metatable __pairs ideas (which of course don't 
address the basic 'for' issue for regular meta-free tables).

-Lucas