three bugs and their fixes in comm() function

first one:

`        $this->write($com, ($count===0));`

second (query commands need to be send with question mark)

```
                    case "?":
                        $el = "?$k=$v";
```

third (hang forever):

```
                $last = ($i === $count - 1);
                $this->write($el, $last);
				$i++;
```