PWM problem on E0 with Megatronics board.

[Francis663]

Symptom: Hotend E0 PID is not working: Temperature reaches the target, stops heating and goes down until timeout.
I searched in the source code and find that the PWM command does not work for E0: 255 value will provide full power, but values between 0 and 254 provide no power.
The Megatronics board set the E0 to pin 2 (OC3B/INT4) PE4 on ATMega2560 CPU.

I swaped the pin for E0 and E1 (pin 9 on PH6 (OC2B)) and is working well. I think it's a problem on PWM setting for E0 when it's on pin 2.