Reset SF can now reset individual telemetry items (fix #161)

radio/src/telemetry/telemetry.cpp

@@ -453,6 +453,23 @@ int availableTelemetryIndex()
   return -1;
 }
 
+int lastUsedTelemetryIndex()
+{
+  for (int index=TELEM_VALUES_MAX-1; index>=0; index--) {
+    TelemetrySensor & telemetrySensor = g_model.telemetrySensors[index];
+    if (telemetrySensor.isAvailable()) {
+      return index;
+    }
+  }
+  return -1;
+}
+
+bool isSensorAvailableInResetSpecialFunction(int index)
+{
+  TelemetrySensor & telemetrySensor = g_model.telemetrySensors[index-FUNC_RESET_PARAM_FIRST_TELEM];
+    return telemetrySensor.isAvailable();
+}
+
 void setTelemetryValue(TelemetryProtocol protocol, uint16_t id, uint8_t instance, int32_t value, uint32_t unit, uint32_t prec)
 {
   int index = getTelemetryIndex(protocol, id, instance);

radio/src/telemetry/telemetry.h

@@ -185,6 +185,8 @@ inline bool isTelemetryFieldComparisonAvailable(int index)
 void setTelemetryValue(TelemetryProtocol protocol, uint16_t id, uint8_t instance, int32_t value, uint32_t unit, uint32_t prec);
 void delTelemetryIndex(uint8_t index);
 int availableTelemetryIndex();
+int lastUsedTelemetryIndex();
+bool isSensorAvailableInResetSpecialFunction(int index);
 int32_t getTelemetryValue(uint8_t index, uint8_t & prec);
 int32_t convertTelemetryValue(int32_t value, uint8_t unit, uint8_t prec, uint8_t destUnit, uint8_t destPrec);