* Removed generic snapmaker machine and toolhead configuration. The idea of running a CNC code that is not matched to the machine's abilities and work area seems dangerous.
* --machine argument is required
* --toolhead argument is required when the selected machine is compatible with more than one toolhead. When the selected machine only supports one toolhead, it is selected as the default.
* --spindle-percent defaults according to the selected toolhead capabilities. If the toolhead can do RPM, then RPM is used, otherwise falls back to percent. This option now functions as an override.
* fixed a bug in convert_spindle() when RPM is selected. The gcode was not returned.
The test was NOT functioning as required.
assert True does NOT compare the expected line with the generated GCode line.
After fixing this, the expected output was updated so that the unit tests pass.
