prefer "Isabelle DejaVu Sans", even for headless batch-build (session_graph.pdf);

clarified signature: fonts are not dependent on GUI;

tuned signature;

clarified signature;

avoid loading of font file, to eliminate "Illegal reflective access by com.lowagie.text.pdf.MappedRandomAccessFile$1 (iText-2.1.5.jar) to method java.nio.DirectByteBuffer.cleaner()" -- due to com.lowagie.text.pdf.TrueTypeFont.process() / RandomAccessFileOrArray;

proper font file name for HTTP (amending dc9a39c3f75d); clarified Entry content;

clarified order;

tuned whitespace;