~mrp/roaster_display_arduino

Update readme.rst
Add readme.rst
Add LICENSE
add serial IO for sending temps to Artisan
change wiring for display to free up serial port
try to make RoR more accurate in the case of the thermocouple returning NaN for a while

When the thermocouple board returns NaN for a while and then returns a temperature the
temperature smoothing smears the change (that happened over a relatively long time)
over several probably smaller samples. This causes the RoR to become inaccurate because
the rate of change is calculated over the later, smaller samples instead of only the span
when there was not a valid temperature to calculate with. This commit changes the
smoothing applied to the temperature so the longer it has been since a valid temperature,
less weight is applied to the past temperature, and more is applied to the valid
temperature when one is returned.
try to make RoR more accurate
make temperature readouts redder if bad readings
finish rewrite to loop continuously
rewrite to loop continuously, not tested yet
improve RoR accuracy, refactor timer code, make style more consistent
clean up code and adjust smoothing parameters
add check for nan result on environment thermocouple
initial commit