Third time's a charm! No more deceleration issues! Updated grbl version and settings. General cleanup.

- Fleshed out the original idea to completely remove the long slope at
the end of deceleration issue. This third time should absolutely
eliminate it.
- Changed the acceleration setting to kept as mm/min^2 internally,
since this was creating unneccessary additional computation in the
planner. Human readable value kept at mm/sec^2.
- Updated grbl version 0.7d and settings version to 4. NOTE: Please
check settings after update. These may have changed, but shouldn't.
- Before updating the new features (pause, e-stop, federate override,
etc), the edge branch will soon be merged with the master, barring any
immediate issues that people may have, and the edge branch will be the
testing ground for the new grbl version 0.8.

gcode.c

@@ -116,9 +116,6 @@ uint8_t gc_execute_line(char *line) {
   
   double p = 0, r = 0;
   int int_value;
-  
-  clear_vector(target);
-  clear_vector(offset);
 
   gc.status_code = STATUS_OK;
   
@@ -171,6 +168,7 @@ uint8_t gc_execute_line(char *line) {
   if (gc.status_code) { return(gc.status_code); }
 
   char_counter = 0;
+  clear_vector(target);
   clear_vector(offset);
   memcpy(target, gc.position, sizeof(target)); // i.e. target = gc.position
 
@@ -388,4 +386,4 @@ static int next_statement(char *letter, double *double_ptr, char *line, uint8_t
    group 9 = {M48, M49} enable/disable feed and speed override switches
    group 12 = {G54, G55, G56, G57, G58, G59, G59.1, G59.2, G59.3} coordinate system selection
    group 13 = {G61, G61.1, G64} path control mode
-*/
+*/