umlauts in UTF-8

Hi Matt,
please review the changes I made. I had some Umlaut-issues when writing gedcom files using your library. It seems that the java internal UTF-16 string representation was not written to the output stream correctly. Changes as extracting the determination of the line break could be extracted accordingly for the other encoding strategies in GedcomFileWriter accordingly if required.
Thanks for the great library!
Best regards,
Max