Minor code and comment polishing

Marlin/Marlin_main.cpp

     plan_bed_level_matrix = matrix_3x3::create_look_at(planeNormal);
     //bedLevel.debug("bedLevel");
 
-    plan_bed_level_matrix.debug("bed level before");
+    //plan_bed_level_matrix.debug("bed level before");
     //vector_3 uncorrected_position = plan_get_position_mm();
     //uncorrected_position.debug("position before");
 
-    // and set our bed level equation to do the right thing
-//    plan_bed_level_matrix = matrix_3x3::create_inverse(bedLevel);
-//    plan_bed_level_matrix.debug("bed level after");
-
     vector_3 corrected_position = plan_get_position();
 //    corrected_position.debug("position after");
     current_position[X_AXIS] = corrected_position.x;
     current_position[Z_AXIS] = corrected_position.z;
 
     // but the bed at 0 so we don't go below it.
-    current_position[Z_AXIS] = -Z_PROBE_OFFSET_FROM_EXTRUDER; // in the lsq we reach here after raising the extruder due to the loop structure
+    current_position[Z_AXIS] = -Z_PROBE_OFFSET_FROM_EXTRUDER;
 
     plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);
 }

Marlin/vector_3.cpp

 
 matrix_3x3 matrix_3x3::create_look_at(vector_3 target)
 {
-    vector_3 z_row = vector_3(target.x, target.y, target.z).get_normal();
+    vector_3 z_row = target.get_normal();
     vector_3 x_row = vector_3(1, 0, -target.x/target.z).get_normal();
     vector_3 y_row = vector_3(0, 1, -target.y/target.z).get_normal();
 
 
  
      // create the matrix already correctly transposed
-    matrix_3x3 rot = matrix_3x3::create_from_rows(vector_3(x_row.x, x_row.y, x_row.z),
-                                vector_3(y_row.x, y_row.y, y_row.z),
-                                vector_3(z_row.x, z_row.y, z_row.z));
+    matrix_3x3 rot = matrix_3x3::create_from_rows(x_row, y_row, z_row);
 
  //   rot.debug("rot");
     return rot;