Refactored offset handling, for improved readability and in preparation for rotation support.

Added experimental support for G66 (modal macro call) and G67 (end modal macro call).
Made axis letter to axis/motor assignment for axes ABCUVW freely changeable at compile time.
Fix for some G65 arguments being incorrectly validated for normal use (sign, range).
Added repeat support to G65 macro call via the optional L parameter word.
Changed default setting for ABC-axes to rotary.
Changed defaults for jerk settings to 10x acceleration settings.
Disabled jerk for jog, probe and spindle synchronized motion.
Added _active_probe system parameter, returns -1 if no probe inputs available.
Minor bug fix, G5.1 and G33.1 motion commands were not coverted to the correct string equivalent in $G output.

pid.c

@@ -3,24 +3,24 @@
 
   PID algorithm for closed loop control
 
-  NOTE: not referenced in the core grbl code
+  NOTE: not referenced in the core grblHAL code
 
   Part of grblHAL
 
   Copyright (c) 2020-2021 Terje Io
 
-  Grbl is free software: you can redistribute it and/or modify
+  grblHAL is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 
-  Grbl is distributed in the hope that it will be useful,
+  grblHAL is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
-  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
   GNU General Public License for more details.
 
   You should have received a copy of the GNU General Public License
-  along with Grbl.  If not, see <http://www.gnu.org/licenses/>.
+  along with grblHAL. If not, see <http://www.gnu.org/licenses/>.
 */
 
 #include <string.h>