Merge pull request #1177 from martin-pr/probing_z_speed

Split do_blocking_move() to XY and Z sections

Marlin/Marlin_main.cpp

 static void do_blocking_move_to(float x, float y, float z) {
     float oldFeedRate = feedrate;
 
+    feedrate = homing_feedrate[Z_AXIS];
+
+    current_position[Z_AXIS] = z;
+    plan_buffer_line(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS], feedrate/60, active_extruder);
+    st_synchronize();
+
     feedrate = XY_TRAVEL_SPEED;
 
     current_position[X_AXIS] = x;
     current_position[Y_AXIS] = y;
-    current_position[Z_AXIS] = z;
     plan_buffer_line(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS], feedrate/60, active_extruder);
     st_synchronize();