#28 remove pre-generated variable from *-font-metrics.php files

[tonda13]

These static pre-generated variable $fontkey rewrite custom name of '''font family''' specified in AddFont() method.

[Humphreybas]

You could also change the $fontkey value back to the custom value after loading the metrics in tfpdf.php:

	if (file_exists($unifilename.'.mtx.php')) {
		include($unifilename.'.mtx.php');
	}
	$fontkey = $family.$style;

Then you don't have to worry about it again.