* new ESPNOWRadio driver

* refactored the examples/*/main.cpp modules, moving radio specifics to variants/*/target modules
* new Generic_ESPNOW_* target envs

src/helpers/ESP32Board.h

@@ -34,7 +34,9 @@ public:
   #endif
 
   #if defined(PIN_BOARD_SDA) && defined(PIN_BOARD_SCL)
+   #if PIN_BOARD_SDA >= 0 && PIN_BOARD_SCL >= 0
     Wire.begin(PIN_BOARD_SDA, PIN_BOARD_SCL);
+   #endif
   #else
     Wire.begin();
   #endif

src/helpers/esp32/ESPNOWRadio.cpp

@@ -50,6 +50,10 @@ void ESPNOWRadio::begin() {
   }
 }
 
+void ESPNOWRadio::setTxPower(uint8_t dbm) {
+  esp_wifi_set_max_tx_power(dbm * 4);
+}
+
 uint32_t ESPNOWRadio::intID() {
   uint8_t mac[8];
   memset(mac, 0, sizeof(mac));
@@ -58,7 +62,7 @@ uint32_t ESPNOWRadio::intID() {
   memcpy(&n, &mac[0], 4);
   memcpy(&m, &mac[4], 4);
   
-  return n * m;
+  return n + m;
 }
 
 void ESPNOWRadio::startSendRaw(const uint8_t* bytes, int len) {

src/helpers/esp32/ESPNOWRadio.h

@@ -23,6 +23,7 @@ public:
 
   float packetScore(float snr, int packet_len) override { return 0; }
   uint32_t intID();
+  void setTxPower(uint8_t dbm);
 };
 
 #if ESPNOW_DEBUG_LOGGING && ARDUINO