Initializing mPDF with own config

[Michal-Erben]

mPDF is initialized with this line$mpdf = new Mpdf($this->getMPDFConfig()); which is correct, but then the extension goes again through those config values in build() function on line 523 and tries to set them as a variables to mPDF which may result in errors, because mPDF does not have those parameters as variables. I don't know if this for is there for any specific reasons, but for me it only resulted in using just mPDF, because I could not set some config values, which were necessary for my code.