CoAP communication BSD socket API based

Functions
void	coap_init (int ip_family, struct sockaddr *addr)
	Open socket and start the receiving thread.
int	coap_send_request (enum coap_method method, const struct sockaddr *addr, const char *const *uri_path_options, uint8_t *payload, uint16_t payload_size, coap_reply_t reply_cb)
	Send CoAP non-confirmable request.

Detailed Description