Customizable titlebar format

[jdpurcell]

When I implemented #375 in my master branch, it got me thinking it would be nice to have a "Custom" option for the "Titlebar text" setting, which gives a textbox to specify the format, with placeholders such as the following:

%n - filename
%i - index in folder
%c - folder file count
%s - filesize
%w - width
%h - height
%z - zoom level

[Andreas0602]

It would be great if you would implement this!

[jurplel]

Yeah this would be cool for sure. I think it would have to come with a settings dialog rewrite since it's already getting crowded in there,

[jdpurcell]

Implemented here! Not sure if it's official-qView-worthy due to the settings UI.

[Hrxn]

Nice, thanks a lot!