Update DHT.h

Author: SConaway

DHT.h

@@ -42,6 +42,7 @@ class DHT {
    float readTemperature(bool S=false, bool force=false);
    float convertCtoF(float);
    float convertFtoC(float);
+   float computeHeatIndex(bool isFahrenheit=true);
    float computeHeatIndex(float temperature, float percentHumidity, bool isFahrenheit=true);
    float readHumidity(bool force=false);
    boolean read(bool force=false);