Smile: improve and add to output, fix cooling-bug

All changes:

• Add domestic_hot_water_setpoint to the output. Will become an additional Number in Plugwise(-beta).
• Create separate dicts for domestic_hot_water_setpoint, maximum_boiler_temperature, and thermostat in the output.
• Change set_max_boiler_temperature() to set_number_setpoint() and make it more general so that more than one Number setpoint can be changed.
• Fix a cooling-related bug (Anna + Elga).
• Improve set_temperature()function.
• Update the testcode accordingly.