URL re-parser is broken

https://github.com/darkain/altaform-core/commit/6cfbcc643ab05148e264ff7b49ca33edc8b1523f
Example:

```
<?php $afurl->reparse(['_altaform']);
```

we cannot test against:
```
ctype_alnum(substr($this->part[$i], 0, 1))
```