Enhancements:
- Implemented M143 and M350
- Wait until movement finished when processing M906
- Allow for additional axes in M906 reporting code
- Added support for external drivers module
- Aux2 device support is now conditional
- Added separate error code for temperature above safety limit
Bug fixes:
- Fixed spurious error report when processing corrupt input line
- When there is a temperature error, return the correct error code
- Update the overheat ADC value when changing thermistor parameters
- Fixed occasional divide by zero problem in PrintMonitor that led to
AJAX errors
- Cold extrusion prevention only checks the active tool, to allow the
same extruder and heater to be configured in multiple tools
- If extrusion is prevented because of a temperature fault, display a
message instead of silently preventing extrusion
