Add in new function coap_mcast_per_resource() to enable granularity of
handling multicast requests differently at the resource level.
The granularity is handled by how the flags variable is set up in
coap_resource_init(). These additional flags are ignored if
function coap_mcast_per_resource() has not been invoked.
Added 2 functions coap_resource_unknown_init2() and
coap_resource_proxy_uri_init2() that support defining the mcast flags as
per coap_resource_init().
Responses are now delayed rather than the request being delayed before being
passed to the request handler.
Update coap-server with the -r option to enable multicast on specific
resources.
Do not reset wait_ms in coap-client for Block2 transfers.
Jon Shallow
88ae9563e6