Update URL in createTemperatureLookupMarlin.py

buildroot/share/scripts/createTemperatureLookupMarlin.py

 http://en.wikipedia.org/wiki/Steinhart-Hart_equation
 
 The main use is for Arduino programs that read data from the circuit board described here:
-http://make.rrrf.org/ts-1.0
+http://reprap.org/wiki/Temperature_Sensor_v2.0
 
 Usage: python createTemperatureLookup.py [options]