Better sensors (#154)

* globally expose repeat functionality as advanced function

* implement repeated sends for Arduino based boards

* use String class instead of C-style arrays to benefit from dynamic allocation and avoid buffer overflows. Try to improve stability of BME280.

* replace sprintf with String class to avoid buffer overruns by dynamic allocation

* fix caps on variable

* re-add TSL2561 code that was accidentally removed

ZsensorADC.ino

@@ -28,7 +28,7 @@
 */
 #ifdef ZsensorADC
 
-#if defined(ESP8266) || defined(ESP32)
+#if defined(ESP8266)
   ADC_MODE(ADC_TOUT);
 #endif
 
@@ -47,11 +47,9 @@ void MeasureADC(){
       trc(F("Failed to read from ADC !"));
     }else{
       if(val  >= persistedadc + ThresholdReadingADC || val  <= persistedadc - ThresholdReadingADC){
-        char value[4];
-        sprintf(value, "%d", val);
         trc(F("Sending analog value to MQTT"));
         trc(String(val));
-        client.publish(ADC,value);
+        client.publish(ADC,String(val).c_str());
         persistedadc = val;
        }
     }