Issue 318: pdf filter does html escapeing in title twice.

Im using debian 8.5 with pdftotext 0.26.5 and the recoll-package 1.22.3 from the download-page.

In Pdfs that has an single quotation mark (') in title this is encoded by pdftotext and rclpdf. So it shows like this:

<title >c't - 23/2008</title >

Check for newer pdftotext version to avoid double HTML escaping. fixes issue #318

→ <<cset d480a6b05234 > >

Check for newer pdftotext version to avoid double HTML escaping. fixes issue #318

→ <<cset d669a06085d1 > >