updates to elimate unused variables and enhance readme

2015_day_3/erronius code

@@ -115,7 +115,7 @@ void movesouth(Housearray* f, char direction){
     for (int i = 0; i< old_rows; ++i){
       new_grid[i] = f->houses[i];
     }
-    new_grid[0] = (int*)calloc(new_cols, sizeof(int));//Initialising the new row to empty
+    new_grid[new_rows - 1] = (int*)calloc(new_cols, sizeof(int));//Initialising the new row to empty
     free(f->houses);
     f->houses = new_grid;
     f->rows·in·array = new_rows;