Update of CoapBlip to draft-ietf-core-coap-13

The TinyOS CoAP implementation is updated to draft-ietf-core-coap-13 (there were no changes in the wire format since draft-ietf-core-coap-13 until draft-ietf-core-coap-18).

It includes CoAP resources for the ETSI interoperability plugtests.
It includes GenaralIO resources. (Fixes #131)
It can handle POST and DELETE now.
Updated to version 4.0.2 of libcoap.