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/report.c

@@ -136,6 +136,8 @@ void report_feedback_message(uint8_t message_code)
     printPgmString(PSTR("Disabled")); break; 
     case MESSAGE_SAFETY_DOOR_AJAR:
     printPgmString(PSTR("Check Door")); break;
+    case MESSAGE_PROGRAM_END:
+    printPgmString(PSTR("Pgm End")); break;
   }
   printPgmString(PSTR("]\r\n"));
 }
@@ -420,7 +422,7 @@ void report_realtime_status()
   // the system power on location (0,0,0) and work coordinate position (G54 and G92 applied). Eventually
   // to be added are distance to go on block, processed block id, and feed rate. Also a settings bitmask
   // for a user to select the desired real-time data.
-  uint8_t i;
+  uint8_t idx;
   int32_t current_position[N_AXIS]; // Copy current state of the system position variable
   memcpy(current_position,sys.position,sizeof(sys.position));
   float print_position[N_AXIS];
@@ -445,21 +447,21 @@ void report_realtime_status()
   // Report machine position
   if (bit_istrue(settings.status_report_mask,BITFLAG_RT_STATUS_MACHINE_POSITION)) {
     printPgmString(PSTR(",MPos:")); 
-    for (i=0; i< N_AXIS; i++) {
-      printFloat_CoordValue(print_position[i]);
-      if (i < (N_AXIS-1)) { printPgmString(PSTR(",")); }
+    for (idx=0; idx< N_AXIS; idx++) {
+      printFloat_CoordValue(print_position[idx]);
+      if (idx < (N_AXIS-1)) { printPgmString(PSTR(",")); }
     }
   }
   
   // Report work position
   if (bit_istrue(settings.status_report_mask,BITFLAG_RT_STATUS_WORK_POSITION)) {
     printPgmString(PSTR(",WPos:")); 
-    for (i=0; i< N_AXIS; i++) {
+    for (idx=0; idx< N_AXIS; idx++) {
       // Apply work coordinate offsets and tool length offset to current position.
-      print_position[i] -= gc_state.coord_system[i]+gc_state.coord_offset[i];
-      if (i == TOOL_LENGTH_OFFSET_AXIS) { print_position[i] -= gc_state.tool_length_offset; }    
-      printFloat_CoordValue(print_position[i]);
-      if (i < (N_AXIS-1)) { printPgmString(PSTR(",")); }
+      print_position[idx] -= gc_state.coord_system[idx]+gc_state.coord_offset[idx];
+      if (idx == TOOL_LENGTH_OFFSET_AXIS) { print_position[idx] -= gc_state.tool_length_offset; }    
+      printFloat_CoordValue(print_position[idx]);
+      if (idx < (N_AXIS-1)) { printPgmString(PSTR(",")); }
     }
   }
         
@@ -492,14 +494,13 @@ void report_realtime_status()
     printFloat_RateValue(st_get_realtime_rate());
   #endif    
   
-  #ifdef REPORT_LIMIT_PIN_STATE
+  if (bit_istrue(settings.status_report_mask,BITFLAG_RT_STATUS_LIMIT_PINS)) {
     printPgmString(PSTR(",Lim:"));
-    uint8_t idx;
     for (idx=0; idx<N_AXIS; idx++) {
-      if (LIMIT_PIN & get_limit_pin_mask(idx)) { printString(PSTR("1")); }
-      else { printString(PSTR("0")); }
+      if (LIMIT_PIN & get_limit_pin_mask(idx)) { printPgmString(PSTR("1")); }
+      else { printPgmString(PSTR("0")); }
     }
-  #endif
+  }
   
   #ifdef REPORT_CONTROL_PIN_STATE 
     printPgmString(PSTR(",Ctl:"));