Naming for tuple members

[streamich]

Right now obj members can be named:

t.Object(
  t.prop('name', t.num),
)

However there is no equivalent way to assign names to tuple members:

t.Tuple(
  t.num
)

Could be something like:

t.Tuple(
  t.prop('x', t.num)
)

The tuples could support, both, named and un-named members:

t.Tuple(
  t.prop('x', t.num),
  t.prop('y', t.num),
)

t.Tuple(
  t.num,
  t.num,
)

One could also mix them:

t.Tuple(
  t.prop('x', t.num),
  t.num,
)

Right now this could be partially accomplished with introducing an unnecessary t.Ref() in the middle.