Limit/control pin state reporting option

- As a setup feature, users can compile-in input pin status reporting.
Doesn’t do anything special, just prints the binary for the port. 0’s
and 1’s indicate low and high signals on the pins. It’s a bit cryptic
right now, but it’s just a start.

- Added a max step rate check when writing step/mm and max rate
settings. Should help avoid people misdiagnosing problems associated
with going over the 30kHz step rate limit. Right now not enabled. Takes
up over 100k of flash. Need that room for other things right now.

report.c

@@ -75,6 +75,8 @@ void report_status_message(uint8_t status_code)
       printPgmString(PSTR("Homing not enabled")); break;
       case STATUS_OVERFLOW:
       printPgmString(PSTR("Line overflow")); break; 
+      // case STATUS_MAX_STEP_RATE_EXCEEDED: 
+      // printPgmString(PSTR("Step rate > 30kHz")); break;
       
       // Common g-code parser errors.
       case STATUS_GCODE_MODAL_GROUP_VIOLATION:
@@ -449,5 +451,12 @@ void report_realtime_status()
     printFloat_RateValue(st_get_realtime_rate());
   #endif    
   
+  #ifdef REPORT_INPUT_PIN_STATES
+    printPgmString(PSTR(",Lim:"));
+    print_uint8_base2(LIMIT_PIN & LIMIT_MASK);  
+    printPgmString(PSTR(",Ctl:"));
+    print_uint8_base2(CONTROL_PIN & CONTROL_MASK);
+  #endif
+  
   printPgmString(PSTR(">\r\n"));
 }