Allowing W axis for G33.1 rigid tapping

[alkabal]

https://github.com/machinekit/machinekit/blob/9239acbee0f84edd94615b5e33e40e724c913ff9/src/emc/rs274ngc/interp_convert.cc#L4571

I try adding W axis to rigid tapping ?

It is possible to merge if created patch work fine ?

[alkabal]

This is for use with motorized linear tailstock.

Br