[core] response code 2.06 versus 5.03

[peter van der Stok]

Hi Core,

I had the pleasure to present the "pending" draft at the start of the
Friday session.
The draft proposes a new coap response code 2.06.
Carsten remarked that response code 5.03 also exists.

Our 2.06 draft allows to specify the location of the result, allowing
interleaved requests.
Additionally, the 2.06 draft will allow multiple requests.

My intention is to not only specify a minimum retry interval but also a
maximum interval (not specified for 5.03)

Consequently, I think that there are enough reasons to continue the 2.06
proposal.

Alternatively, the 5.03 can be extended with the current 2.06
specification.

Peter