Dynamic calculation of temp_step
Adding wiring notes
Removing states debug code
Ensuring fan is on at least partial if heat is on
Switching thermocouple pins
Turning on fan partial in ROAST_PREHEAT stage
Renaming; not shutting down on error; globalizing internal_temp
Switching to library pins for thermocouple; not shutting down on error
Separating heat gun and heating element pins
Changint TEMP_STEP to const int = 5
Better debug output
Fixing heat_on() call in HEAT_FULL

Removing extra debug statements because they're looped over too much
Adding element_state control for heating elements, gun
Casting operations to double for temp_stemp
Printing elapsed time in minutes for temp readings