Fix PDF file properties in Book 2

[jhlegarreta]

As discussed in PR #73, Book 2 PDF file properties seem not to be created as expected; taking one of the latest builds, the PDF properties show:

Title: MultiResImageRegistration1TraceMetric.eps
Author: aghayoor
Subject: gnuplot plot
Keywords: "Registration,Segmentation,Guide"

and the following is expected:

Title: ITK Software Guide
Author: Hans Johnson and Luis Ibáñez and Matthew McCormick and the Insight Software Consortium
Subject: Medical Image Segmentation and Registration Toolkit
Keywords: "Registration,Segmentation,Guide"