added -dNEWPDF=false to all ghostscript commands in order to enforce …

[bkroggel]

As mentioned in #28 the Ghostscript team has rewritten the PDF interpreter in C rather than the old PostScript one. This led to an output where elements didn‘t get centered anymore although specified otherwise.

This fix does not adapt pdfScale to the new interpreter but solely adds a flag that allows the tool to (for now) make use of the PostScript interpreter.

Fix #28