Enable cloud serial comms to individual devices

The Particle Cloud API and ParticleJS do not appear to allow publishing
events to specific devices. This change works around that limitation by
having the Oaks listen to /oak/device/stdin/:deviceid and
/oak/device/reset/:deviceid so that they can be individually addressed.

The Oaks are also still listening to /oak/device/stdin and
/oak/device/reset so that all of one's Oaks can be addressed
simultaneously if desired.

cores/oak/OakParticle/particle_core.cpp

@@ -2792,6 +2792,9 @@ const char* RESET_EVENT = "spark/device/reset";
 const char* OAK_RESET_EVENT = "oak/device/reset";
 const char* OAK_RX_EVENT = "oak/device/stdin";
 
+#define OAK_RESET_EVENT_LEN 16
+#define OAK_RX_EVENT_LEN    16
+
 void SystemEvents(const char* name, const char* data)
 {
     if (!strncmp(name, CLAIM_EVENTS, strlen(CLAIM_EVENTS))) {
@@ -2810,7 +2813,10 @@ void SystemEvents(const char* name, const char* data)
                 ESP.reset();
         }
     }
-    if (!strcmp(name, OAK_RESET_EVENT)) {
+    if (!strncmp(name, OAK_RESET_EVENT, OAK_RESET_EVENT_LEN) &&
+        (name[OAK_RESET_EVENT_LEN] == 0 ||
+        (name[OAK_RESET_EVENT_LEN] == '/' &&
+        !strcmp((name+OAK_RESET_EVENT_LEN+1),deviceConfig->device_id)))) {
         if (data && *data) {
             if (!strcmp("config mode", data))
                 reboot_to_config();
@@ -3180,7 +3186,11 @@ void spark_get_rx(const char* name, const char* data){ //this is automatically c
   if(spark_serial_state < 2){
     return;
   }
-
+    if ((name[OAK_RX_EVENT_LEN] != 0 &&
+        (name[OAK_RX_EVENT_LEN] != '/' ||
+        strcmp((name+OAK_RX_EVENT_LEN+1),deviceConfig->device_id)))) {
+        return;
+    }
     if (data && *data) {
 
         while(*data != '\0'){