Bug#891414: enable qt5 front-end

[E. Serradilla]

Package: gimagereader
Version: 3.2.3-2

please enable qt5 front-end, a sample packaging for debian with both gtk 
and qt fron-ends is available in the source code:

https://github.com/manisandro/gImageReader/tree/master/packaging/debian

you might also need qtspell package:

https://github.com/manisandro/qtspell

tested in Stretch with gimagereader 3.2.99 which also adds support for 
djvu files, many thanks.