gscan2pdf v1.3.3 released

[Jeffrey Ratcliffe <jeffrey ratcliffe gmail com>]

gscan2pdf - A GUI to produce a multipage PDF or DjVu from a scan.

http://gscan2pdf.sourceforge.net/

Five clicks are required to scan several pages and then save all or
a selection as a PDF or DjVu file, including metadata if required.

gscan2pdf can control regular or sheet-fed (ADF) scanners with SANE via
libsane-perl, scanimage or scanadf, and can scan multiple pages at
once. It presents a thumbnail view of scanned pages, and permits simple
operations such as cropping, rotating and deleting pages.

OCR can be used to recognise text in the scans, and the output
embedded in the PDF or DjVu.

PDF conversion is done by PDF::API2.

The resulting document may be saved as a PDF, DjVu, multipage TIFF file,
or single page image file.

Changelog for 1.3.3:
* Suppress warnings when passed boolean as empty string
  Closes LP: #844582 ("Invalid argument" when trying to scan)
* Moved config file format to JSON. JSON::PP is a core module,
  so this does not create a new dependency.
* + option not to show dialog messages
* Trap errors from unpaper, rotate, crop, threshold, negate, unsharp
  processing tools
  Closes bug #198 (empty pages when saving, GIMP, or printing)
* Removed dependency on liblinux-distribution-perl as not available on FreeBSD
* Also support gconftool-2 when checking for email client
  Closes bug #200 (it doesn't attach on Fedora 21 (with thunderbird))
* Update to German translation (thanks to Tobias Bannert)
* Fixed program hang importing an empty file at the same time as other files
* Rewrite threading system to simplify it and remove many race conditions
* Fixed bug setting threshold-before-ocr check box