The retransmission timeout is more accurate now by using floating point
arithmetic.
For better readability, the parameter names from RFC 7252 are used.
Adding and removal of observes is now handled by libcoap. The application's
GET handler only needs to add the Observe option (see server.c:hnd_get_time()).
This new behavior is described in Section 4.6 of draft-ietf-core-observe-12.
The idea is to send a response with code 7.31 and the token to identify
the subscription.
This change provides basic support for block-wise transfer of resource
descriptions. print_wellknown() now takes an additional parameter that
specifies the offset in the resource description where output shall start.
coap_print_link() has been modified to truncate resource descriptions that
do not fit in the given buffer (instead of failing with an error code as
was the case before).
Olaf Bergmann