Fixed the display initialization. The shutdown mode and display test mode needed to be turned off.
Removed the leading zeros from the 7-segment display.
Re-introduced the PID scaling factor, but only for the integral constant.
Added an threshold for the integral of the PID controller. The integral will be only be increased/decreased when the process value is closer to the setpoint than the threshold value.
Fixed a bug that occurred when using an invalid :GET:STATE serial command.