Homing alarm upon no switch. Licensing update.

- Homing cycle failure reports alarm feedback when the homing cycle is
exited via a reset, interrupted by a safety door switch, or does not
find the limit switch.

- Homing cycle bug fix when not finding the limit switch. It would just
idle before, but now will exit with an alarm.

- Licensing update. Corrected licensing according to lawyer
recommendations. Removed references to other Grbl versions.

grbl/protocol.c

@@ -1,8 +1,9 @@
 /*
   protocol.c - controls Grbl execution protocol and procedures
-  Part of Grbl v0.9
-
-  Copyright (c) 2012-2015 Sungeun K. Jeon  
+  Part of Grbl
+  
+  Copyright (c) 2011-2015 Sungeun K. Jeon  
+  Copyright (c) 2009-2011 Simen Svale Skogsrud
 
   Grbl is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -17,12 +18,6 @@
   You should have received a copy of the GNU General Public License
   along with Grbl.  If not, see <http://www.gnu.org/licenses/>.
 */
-/* 
-  This file is based on work from Grbl v0.8, distributed under the 
-  terms of the MIT-license. See COPYING for more details.  
-    Copyright (c) 2009-2011 Simen Svale Skogsrud
-    Copyright (c) 2011-2012 Sungeun K. Jeon
-*/ 
 
 #include "grbl.h"
 
@@ -198,6 +193,8 @@ void protocol_execute_realtime()
       report_alarm_message(ALARM_ABORT_CYCLE);
     } else if (rt_exec & EXEC_ALARM_PROBE_FAIL) {
       report_alarm_message(ALARM_PROBE_FAIL);
+    } else if (rt_exec & EXEC_ALARM_HOMING_FAIL) {
+      report_alarm_message(ALARM_HOMING_FAIL);
     }
     // Halt everything upon a critical event flag. Currently hard and soft limits flag this.
     if (rt_exec & EXEC_CRITICAL_EVENT) {