Critical M0/2/30 fix. Homing updates.

- Critical fix for M0 program pause. Due to its recent change, it would
cause Grbl to suspend but wouldn’t notify the user of why Grbl was not
doing anything. The state would show IDLE and a cycle start would
resume it. Grbl now enters a HOLD state to better indicate the state
change.

- Critical fix for M2 and M30 program end. As with M0, the state
previously would show IDLE while suspended. Grbl now does not suspend
upon program end and leaves job control to the GUI. Grbl simply reports
a `[Pgm End]` as a feedback message and resets certain g-code modes.

- M2/30 g-code reseting fix. Previously Grbl would soft-reset after an
M2/30, but this was not complaint to the (linuxcnc) g-code standard. It
simply resets [G1,G17,G90,G94,G40,G54,M5,M9,M48] and keeps all other
modes the same.

- M0/M2/M30 check-mode fix. It now does not suspend the machine during
check-mode.

- Minor bug fix related to commands similar to G90.1, but not G90.1,
not reporting an unsupported command.

- Homing cycle refactoring. To help reduce the chance of users
misunderstanding their limit switch wiring, Grbl only moves a short
distance for the locate cycles only. In addition, the homing cycle
pulls-off the limit switch by the pull-off distance to re-engage and
locate home. This should improve its accuracy.

- HOMING_FORCE_ORIGIN now sets the origin to the pull-off location,
rather than where the limit switch was triggered.

- Updated default junction deviation to 0.01mm. Recent tests showed
that this improves Grbl’s cornering behavior a bit.

- Added the ShapeOko3 defaults.

- Added new feedback message `[Pgm End]` for M2/30 notification.

- Limit pin reporting is now a $10 status report option. Requested by
OEMs to help simplify support troubleshooting.

grbl/defaults.h

@@ -49,7 +49,6 @@
   #define DEFAULT_JUNCTION_DEVIATION 0.02 // mm
   #define DEFAULT_ARC_TOLERANCE 0.002 // mm
   #define DEFAULT_REPORT_INCHES 0 // false
-  #define DEFAULT_AUTO_START 1 // true
   #define DEFAULT_INVERT_ST_ENABLE 0 // false
   #define DEFAULT_INVERT_LIMIT_PINS 0 // false
   #define DEFAULT_SOFT_LIMIT_ENABLE 0 // false
@@ -87,10 +86,9 @@
   #define DEFAULT_DIRECTION_INVERT_MASK ((1<<Y_AXIS)|(1<<Z_AXIS))  
   #define DEFAULT_STEPPER_IDLE_LOCK_TIME 25 // msec (0-254, 255 keeps steppers enabled)
   #define DEFAULT_STATUS_REPORT_MASK ((BITFLAG_RT_STATUS_MACHINE_POSITION)|(BITFLAG_RT_STATUS_WORK_POSITION))
-  #define DEFAULT_JUNCTION_DEVIATION 0.02 // mm
+  #define DEFAULT_JUNCTION_DEVIATION 0.01 // mm
   #define DEFAULT_ARC_TOLERANCE 0.002 // mm
   #define DEFAULT_REPORT_INCHES 0 // true
-  #define DEFAULT_AUTO_START 1 // true
   #define DEFAULT_INVERT_ST_ENABLE 0 // false
   #define DEFAULT_INVERT_LIMIT_PINS 0 // false
   #define DEFAULT_SOFT_LIMIT_ENABLE 0 // false
@@ -129,10 +127,9 @@
   #define DEFAULT_DIRECTION_INVERT_MASK ((1<<Y_AXIS)|(1<<Z_AXIS))  
   #define DEFAULT_STEPPER_IDLE_LOCK_TIME 255 // msec (0-254, 255 keeps steppers enabled)
   #define DEFAULT_STATUS_REPORT_MASK ((BITFLAG_RT_STATUS_MACHINE_POSITION)|(BITFLAG_RT_STATUS_WORK_POSITION))
-  #define DEFAULT_JUNCTION_DEVIATION 0.05 // mm
+  #define DEFAULT_JUNCTION_DEVIATION 0.02 // mm
   #define DEFAULT_ARC_TOLERANCE 0.002 // mm
   #define DEFAULT_REPORT_INCHES 0 // false
-  #define DEFAULT_AUTO_START 1 // true
   #define DEFAULT_INVERT_ST_ENABLE 0 // false
   #define DEFAULT_INVERT_LIMIT_PINS 0 // false  
   #define DEFAULT_SOFT_LIMIT_ENABLE 0 // false
@@ -171,10 +168,9 @@
   #define DEFAULT_DIRECTION_INVERT_MASK ((1<<X_AXIS)|(1<<Z_AXIS))
   #define DEFAULT_STEPPER_IDLE_LOCK_TIME 255 // msec (0-254, 255 keeps steppers enabled)
   #define DEFAULT_STATUS_REPORT_MASK ((BITFLAG_RT_STATUS_MACHINE_POSITION)|(BITFLAG_RT_STATUS_WORK_POSITION))
-  #define DEFAULT_JUNCTION_DEVIATION 0.05 // mm
+  #define DEFAULT_JUNCTION_DEVIATION 0.02 // mm
   #define DEFAULT_ARC_TOLERANCE 0.002 // mm
   #define DEFAULT_REPORT_INCHES 0 // false
-  #define DEFAULT_AUTO_START 1 // true
   #define DEFAULT_INVERT_ST_ENABLE 0 // false
   #define DEFAULT_INVERT_LIMIT_PINS 0 // false  
   #define DEFAULT_SOFT_LIMIT_ENABLE 0 // false
@@ -187,6 +183,46 @@
   #define DEFAULT_HOMING_PULLOFF 1.0 // mm  
 #endif
 
+#ifdef DEFAULTS_SHAPEOKO_3
+  // Description: Shapeoko CNC mill with three NEMA 23 stepper motors, driven by CarbideMotion
+  #define MICROSTEPS_XY 8
+  #define STEP_REVS_XY 200
+  #define MM_PER_REV_XY (2.0*20) // 2mm belt pitch, 20 pulley teeth
+  #define MICROSTEPS_Z 8
+  #define STEP_REVS_Z 200
+  #define MM_PER_REV_Z (2.0*20) // 2mm belt pitch, 20 pulley teeth
+  #define DEFAULT_X_STEPS_PER_MM (MICROSTEPS_XY*STEP_REVS_XY/MM_PER_REV_XY)
+  #define DEFAULT_Y_STEPS_PER_MM (MICROSTEPS_XY*STEP_REVS_XY/MM_PER_REV_XY)
+  #define DEFAULT_Z_STEPS_PER_MM (MICROSTEPS_Z*STEP_REVS_Z/MM_PER_REV_Z)
+  #define DEFAULT_X_MAX_RATE 5000.0 // mm/min
+  #define DEFAULT_Y_MAX_RATE 5000.0 // mm/min
+  #define DEFAULT_Z_MAX_RATE 5000.0 // mm/min
+  #define DEFAULT_X_ACCELERATION (400.0*60*60) // 400*60*60 mm/min^2 = 400 mm/sec^2
+  #define DEFAULT_Y_ACCELERATION (400.0*60*60) // 400*60*60 mm/min^2 = 400 mm/sec^2
+  #define DEFAULT_Z_ACCELERATION (400.0*60*60) // 400*60*60 mm/min^2 = 400 mm/sec^2
+  #define DEFAULT_X_MAX_TRAVEL 425.0 // mm
+  #define DEFAULT_Y_MAX_TRAVEL 465.0 // mm
+  #define DEFAULT_Z_MAX_TRAVEL 80.0 // mm
+  #define DEFAULT_STEP_PULSE_MICROSECONDS 10
+  #define DEFAULT_STEPPING_INVERT_MASK 0
+  #define DEFAULT_DIRECTION_INVERT_MASK ((1<<X_AXIS)|(1<<Z_AXIS))
+  #define DEFAULT_STEPPER_IDLE_LOCK_TIME 255 // msec (0-254, 255 keeps steppers enabled)
+  #define DEFAULT_STATUS_REPORT_MASK 255 // All enabled
+  #define DEFAULT_JUNCTION_DEVIATION 0.02 // mm
+  #define DEFAULT_ARC_TOLERANCE 0.01 // mm
+  #define DEFAULT_REPORT_INCHES 0 // false
+  #define DEFAULT_INVERT_ST_ENABLE 0 // false
+  #define DEFAULT_INVERT_LIMIT_PINS 0 // false  
+  #define DEFAULT_SOFT_LIMIT_ENABLE 0 // false
+  #define DEFAULT_HARD_LIMIT_ENABLE 0  // false
+  #define DEFAULT_HOMING_ENABLE 0  // false
+  #define DEFAULT_HOMING_DIR_MASK 0 // move positive dir
+  #define DEFAULT_HOMING_FEED_RATE 100.0 // mm/min
+  #define DEFAULT_HOMING_SEEK_RATE 1000.0 // mm/min
+  #define DEFAULT_HOMING_DEBOUNCE_DELAY 25 // msec (0-65k)
+  #define DEFAULT_HOMING_PULLOFF 5.0 // mm  
+#endif
+
 #ifdef DEFAULTS_ZEN_TOOLWORKS_7x7
   // Description: Zen Toolworks 7x7 mill with three Shinano SST43D2121 65oz-in NEMA 17 stepper motors.
   // Leadscrew is different from some ZTW kits, where most are 1.25mm/rev rather than 8.0mm/rev here.
@@ -214,7 +250,6 @@
   #define DEFAULT_JUNCTION_DEVIATION 0.02 // mm
   #define DEFAULT_ARC_TOLERANCE 0.002 // mm
   #define DEFAULT_REPORT_INCHES 0 // false
-  #define DEFAULT_AUTO_START 1 // true
   #define DEFAULT_INVERT_ST_ENABLE 0 // false
   #define DEFAULT_INVERT_LIMIT_PINS 0 // false  
   #define DEFAULT_SOFT_LIMIT_ENABLE 0 // false
@@ -250,7 +285,6 @@
   #define DEFAULT_JUNCTION_DEVIATION 0.02 // mm
   #define DEFAULT_ARC_TOLERANCE 0.002 // mm
   #define DEFAULT_REPORT_INCHES 0 // false
-  #define DEFAULT_AUTO_START 1 // true
   #define DEFAULT_INVERT_ST_ENABLE 0 // false
   #define DEFAULT_INVERT_LIMIT_PINS 0 // false
   #define DEFAULT_SOFT_LIMIT_ENABLE 0 // false
@@ -286,7 +320,6 @@
   #define DEFAULT_JUNCTION_DEVIATION 0.02 // mm
   #define DEFAULT_ARC_TOLERANCE 0.002 // mm
   #define DEFAULT_REPORT_INCHES 0 // false
-  #define DEFAULT_AUTO_START 1 // true
   #define DEFAULT_INVERT_ST_ENABLE 0 // false
   #define DEFAULT_INVERT_LIMIT_PINS 0 // false
   #define DEFAULT_SOFT_LIMIT_ENABLE 0 // false