Fixed doubling of M301 I parameter and halving of M301 P parameter
Implemented M303 auto tune and M307 heater process model
Improved temperature monitoring to detect heater cartridges or
thermistor falling out
Implemented M38 (thanks chrishamm)
Retructured course code tree
Add support for second SD card on SPI bus for Duet WiFi including
implementation of M21 and M22
New temperature monitoring
Increased PWM resolution
When uploading files to wifi module, skip empty blocks
Revised TMC driver in preparation for standstill current reduction
Fixed PrintMonitor bug when the slicer comment includes a '\' character
Merged in chrishamm's changes to Network, PrintMonitor, and his support
for firmware updates from SD card
Fixed print monitor issue that threw out the layer count and time
estimates when there was an initial extruder priming move in the start
gcode