Add possibility for switching to pdfbox NonSequentialPDFParser

As discussing, we can improve PDF extraction by 45% with this new NonSequentialPDFParser and fit more with PDF specification. This parser will be integrated by default in pdfbox 2.0.

ref.:
https://issues.apache.org/jira/browse/PDFBOX-1104
http://pdfbox.apache.org/ideas.html

We should provide an extended parser or parameter current PDFParser to call:

PDDocument.loadNonSeq(file, scratchFile);