v1.13.1: Version 1.13.1

dspdfviewer v1.13.1
===================

This is a bugfix and maintenance release for v1.13.

Bugfixes:

* Regression: Changing slide while blanked crashed the program

Other:

* A `dspdfviewer.desktop` file has been added, helping desktop enviroments
  to include the program in their menus
* `dspdfviewer --help` informs about the manpage and the F1 help box