Add support for getting multiple services data from advertisments. (#20)

* Add support for getting multiple services data from advertisments.

* Adds new methods for getting advertised service data and UUIDS.
- getServiceData(index), gets the service data by index value.
- getServiceData(NimBLEUUID), gets the service data by UUID.
- getServiceDataCount(), gets the number of services with data advertised.

* Templates added for getServiceData(index) and getServiceData(NimBLEUUID)
  to be able to specify the data type returned by these methods
  Example:
      getServiceData<uint32_t>(NimBLEUUID("ABCD");

* Also added:
- getServiceUUID(index), gets the advertised service UUID by index value.
- getServiceUUIDCount(), gets the number of advertised services.

src/NimBLEScan.cpp

@@ -52,8 +52,6 @@ NimBLEScan::NimBLEScan() {
 /*STATIC*/int NimBLEScan::handleGapEvent(ble_gap_event* event, void* arg) {
 
     NimBLEScan* pScan = (NimBLEScan*)arg;
-    struct ble_hs_adv_fields fields;
-    int rc = 0;
 
     switch(event->type) {
 
@@ -63,13 +61,6 @@ NimBLEScan::NimBLEScan() {
                 return 0;
             }
 
-            rc = ble_hs_adv_parse_fields(&fields, event->disc.data,
-                                     event->disc.length_data);
-            if (rc != 0) {
-                NIMBLE_LOGE(LOG_TAG, "Gap Event Parse ERROR.");
-                return 0;
-            }
-
             NimBLEAddress advertisedAddress(event->disc.addr);
 
             // Examine our list of ignored addresses and stop processing if we don't want to see it or are already connected
@@ -102,9 +93,9 @@ NimBLEScan::NimBLEScan() {
                 NIMBLE_LOGI(LOG_TAG, "UPDATING PREVIOUSLY FOUND DEVICE: %s", advertisedAddress.toString().c_str());
             }
             advertisedDevice->setRSSI(event->disc.rssi);
-            advertisedDevice->parseAdvertisement(&fields);
-            advertisedDevice->setScan(pScan);
-            advertisedDevice->setAdvertisementResult(event->disc.data, event->disc.length_data);
+            if(event->disc.length_data > 0) {
+                advertisedDevice->parseAdvertisement(event->disc.data, event->disc.length_data);
+            }
             advertisedDevice->m_timestamp = time(nullptr);
 
             if (pScan->m_pAdvertisedDeviceCallbacks) {