This merge request adds some missing viewer preferences to ViewerPreferences class and make them available in glib frontend.
Two things I'm not sure about are representations of "PickTrayByPDFSize" and "PrintPageRange" in glib frontend. Whether to have "PickTrayByPDFSize" as a flag and "PrintPageRange" as an array of numbers instead of an array of pairs of numbers. I've set the "PickTrayByPDFSize" as a flag since it is a boolean value and "PrintPageRange" as an array of numbers to not add complexity to accessing of the ranges (maybe it adds some instead...).
This is related to issue #290.