Revert "Stop publish examples to mongoose repo"

This reverts commit 1a17e17c462bdd4e1d26d8742f8b7087273e04c2.

PUBLISHED_FROM=80028de308c9a021955d1425d2bfee8feb85f193

examples/coap_server/Makefile

@@ -0,0 +1,3 @@
+PROG = coap_server
+MODULE_CFLAGS = -DMG_ENABLE_COAP
+include ../examples.mk

examples/coap_server/coap_server.c

@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2015 Cesanta Software Limited
+ * All rights reserved
+ *
+ * This program listens on 5683 for CoAP messages,
+ * sends ACK is nessesary and dump everything received.
+ * It is possible to use ../coap_client to send message.
+ */
+
+#include "mongoose.h"
+
+static char *s_default_address = "udp://:5683";
+static int s_sig_received = 0;
+
+static void signal_handler(int sig_num) {
+  signal(sig_num, signal_handler);
+  s_sig_received = sig_num;
+}
+
+static void coap_handler(struct mg_connection *nc, int ev, void *p) {
+  switch (ev) {
+    case MG_EV_COAP_CON: {
+      uint32_t res;
+      struct mg_coap_message *cm = (struct mg_coap_message *) p;
+      printf("CON with msg_id = %d received\n", cm->msg_id);
+      res = mg_coap_send_ack(nc, cm->msg_id);
+      if (res == 0) {
+        printf("Successfully sent ACK for message with msg_id = %d\n",
+               cm->msg_id);
+      } else {
+        printf("Error: %d\n", res);
+      }
+      break;
+    }
+    case MG_EV_COAP_NOC:
+    case MG_EV_COAP_ACK:
+    case MG_EV_COAP_RST: {
+      struct mg_coap_message *cm = (struct mg_coap_message *) p;
+      printf("ACK/RST/NOC with msg_id = %d received\n", cm->msg_id);
+      break;
+    }
+  }
+}
+
+int main(void) {
+  struct mg_mgr mgr;
+  struct mg_connection *nc;
+
+  signal(SIGTERM, signal_handler);
+  signal(SIGINT, signal_handler);
+
+  mg_mgr_init(&mgr, 0);
+
+  nc = mg_bind(&mgr, s_default_address, coap_handler);
+  if (nc == NULL) {
+    printf("Unable to start listener at %s\n", s_default_address);
+    return -1;
+  }
+
+  printf("Listening for CoAP messages at %s\n", s_default_address);
+
+  mg_set_protocol_coap(nc);
+
+  while (!s_sig_received) {
+    mg_mgr_poll(&mgr, 1000000);
+  }
+
+  printf("Exiting on signal %d\n", s_sig_received);
+
+  mg_mgr_free(&mgr);
+  return 0;
+}