Undefined offset #50
Description
Hi,
I sometimes get undefined offsets at this line:
https://github.com/PhenX/php-font-lib/blob/0.4/src/FontLib/BinaryStream.php#L379
Happened when using Dompdf with font stripping turned on with bold Times New Roman.
It seems to work correctly if I check if $data[$i] is set and return null otherwise.
$ret += $this->w($type[0], isset($data[$i]) ? $data[$i] : null);