Update visibility of millisToWaitForConversion

Switch visibility from private to public for method millisToWaitForConversion.

This method is usefull for mysensor project.
Releated issue in mysensor example
mysensors/MySensorsArduinoExamples#20

Author: Ducatel

DallasTemperature.h

@@ -150,6 +150,8 @@ class DallasTemperature
 
      // Is a conversion complete on the wire?
     bool isConversionComplete(void);
+    
+    int16_t millisToWaitForConversion(uint8_t);
 
 #if REQUIRESALARMS
 
@@ -251,8 +253,6 @@ class DallasTemperature
     // reads scratchpad and returns the raw temperature
     int16_t calculateTemperature(const uint8_t*, uint8_t*);
 
-    int16_t millisToWaitForConversion(uint8_t);
-
     void	blockTillConversionComplete(uint8_t);
 
 #if REQUIRESALARMS