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.

gcode.h

@@ -82,7 +82,11 @@ typedef struct {
   float coord_system[N_AXIS];      // Current work coordinate system (G54+). Stores offset from absolute machine
                                    // position in mm. Loaded from EEPROM when called.
   float coord_offset[N_AXIS];      // Retains the G92 coordinate offset (work coordinates) relative to
-                                   // machine zero in mm. Non-persistent. Cleared upon reset and boot.        
+                                   // machine zero in mm. Non-persistent. Cleared upon reset and boot.    
+                                   
+  float arc_radius; 
+  float arc_offset[N_AXIS];
+                                         
 } parser_state_t;
 extern parser_state_t gc;
 
@@ -93,6 +97,6 @@ void gc_init();
 uint8_t gc_execute_line(char *line);
 
 // Set g-code parser position. Input in steps.
-void gc_set_current_position(int32_t x, int32_t y, int32_t z); 
+void gc_sync_position(); 
 
 #endif