'table' as fallback for tables

[Dirk Laurie <dirk.laurie@...>]

[1]
Tables have individual metatables. Tables freshly constructed
by a table literal have none. The following is an error:

> ({24,6,2016):concat"/"  --> (not yet) 24/6/2016

Would it not be nice if tables that have no metatable fall back
to {__index=table}? [2] Only table.pack does not have a table as
first argument, and we have a precedent for that in 'string',
which is also the __index of a metatable but contains functions
cannot be used with object notation.

[1] Since feature request season seems to be open.
[2] Sean will no doubt be able to cite when this exact proposal
was first made, unless it was before 2009.