WIP: replace RIGID_TAP with SPINDLE_SYNC_MOTION

* replace interp_convert, emccanon, NML, and tp
* TODO:
  + verify the function of G33.1 (RIGID_TAP)
  + implement G33 in tp.c and tc.c
Merge branch 'feature/usb-rigid-tap' of github.com:araisrobo/linuxcnc into feature/usb-rigid-tap
Update INI and FPAG/RISC firmware for araisrobo/miller
glcanon.py: replace rigid_tap() with spindle_sync_motion()