Minimal heat applied at negative power calculation

[jakenl]

While the plugin setting "minimum heating cycle" is set to "only when heat is required", there is in some cases still heat applied while the power calculation <= 0
This happens when the temperature is between setpoint and deltamax (overshoot = false).

My proposal is to change to following line:
# apply minimum power as required
if power <= self.minheatpower and (Parameters["Mode4"] == "Forced" or not overshoot):

to:

    # apply minimum power as required
    if power > 0 and power <= self.minheatpower and (Parameters["Mode4"] == "Forced" or not overshoot):