Parking mode improvements.
Removed requirement for external encoder for spindle sync if stepper spindle is enabled.
Improved handling of $680 stepper enable delay.
these instead of calling via hal.port functions or accessing hal.port properties.
Improved the ioports API, updated core code to make use of it.
Flagged some calls and (part of) some stuctures as deprecated.
Added '$709' setting for second PWM spindle when available - PWM options.
Added properties to PWM spindles to allow "overdriving" PWM output when _RPM controls spindle enable signal is enabled with '$9' or '$709'.
Optimized Modbus CRC calculation, may fix issue with a compiler generating different code compared to most others. Ref. issue #723.
Added HAL parameter for minimum step pulse length set by driver, used for validation of $0 setting.
Changed HAL API signature for outputting step pulses, optimized to allow drivers to only change direction outputs when there is an actual direction change.
Improved handling of overrides at end of program when all motion is buffered. Possible fix for issue #714.
Some optimizations to allow higher step rates.
Improved default serial port mapping when both MPG mode and keypad plugin are enabled to ensure the port is shared.
Delayed status report output on MPG mode change a few milliseconds to avoid awakening the ESP32 guru that sometimes reboots the controller.
Added option to homing enable setting ($22) for per axis homing feedrates.
!! Backup and restore settings over an update is recommended since all settings will be reset to default. Any odometer data will also be lost.
