Compactified the code for the handling of serial communication. However the changes make the program slightly bigger in size.
Resetting the integral now when changing the setpoint or the controller state.
Added possibility to save and recall parameters into and from the EEPROM. At the beginning after a reset the parameters are read and therefore (saved) settings are retained after a power cycle. Parameters include the setpoint and the PID controller factors (for cooling and heating).
Changed conversion from temperature to ADC values to use decimal numbers for more precision.
Fixed bad temperature to ADC lookup table.
Added an OK response to save and recall serial commands.
Fixed conversion from temperature to ADC value (integer overflow).
Fixed the EEPROM addresses (offset between 16 bit integers is 2).
Removed old comment.
Set default state to control off.