Added option to set the filename used when saving the file.
Added option to set the filename used when saving the file.

MichalGrzegorzak/PdfiumViewer,pasysxa/PdfiumViewer,modulexcite/PdfiumViewer,stevewangamm/PdfiumViewer,ballance/PdfiumViewer,pvginkel/PdfiumViewer,MichalGrzegorzak/PdfiumViewer,pvginkel/PdfiumViewer,modulexcite/PdfiumViewer,stevewangamm/PdfiumViewer,ballance/PdfiumViewer,pasysxa/PdfiumViewer