Push old dev_2 draft to work on other things.

- **NON-FUNCTIONAL**
- Contains an old draft of separating the stepper driver direct access
to the planner buffer. This is designed to keep the stepper and planner
modules independent and prevent overwriting or other complications. In
this way, feedrate override should be able to be installed as well.
- A number of planner optimizations are installed too.
- Not sure where the bugs are. Either in the new planner optimizations,
new stepper module updates, or in both. Or it just could be that the
Arduino AVR is choking with the new things it has to do.

main.c

@@ -72,7 +72,8 @@ int main(void)
 
       // Sync cleared gcode and planner positions to current system position, which is only
       // cleared upon startup, not a reset/abort. 
-      sys_sync_current_position();
+      plan_sync_position();
+      gc_sync_position();
 
       // Reset system variables.
       sys.abort = false;
@@ -101,12 +102,12 @@ int main(void)
     }
     
     protocol_execute_runtime();
-    protocol_process(); // ... process the serial protocol
     
     // When the serial protocol returns, there are no more characters in the serial read buffer to
     // be processed and executed. This indicates that individual commands are being issued or 
     // streaming is finished. In either case, auto-cycle start, if enabled, any queued moves.
     mc_auto_cycle_start();
+    protocol_process(); // ... process the serial protocol
     
   }
   return 0;   /* never reached */