Includes a new settings facility with the highlighting being contrled
by a new model class and a modified QListView to display the data for
editing. Edits include enable and disable check boxes, a contextual
pop-up menu to adjust backkground and foreground colours.
Still to be implemented are priorities for highlighting
categories. This will be adjustable by drag and drop in the Colors
settings panel, it is already implemented by the priority order has no
effect on highlighting of decodes yet.
The LotW users data file fetch and time since user's last upload is
now controled from the settings dialog.
This change also drops support for Qt versions before 5.5 so that many
workarounds for earlier versions can be removed.
Debug trace is slightly modified to make better use of the Qt built in
facilities to format and synchronize cross thread messaging.
