Setting fonts only fully takes effect after restart

[lmoureaux]

Describe the bug

https://osdn.net/projects/freeciv/ticket/44850

Confirmed by dino in beta1

Easy solutions:

• Add (requires restart)
• Provide good defaults and remove the options altogether

Additional context

Should go through the style (or stylesheet), as they have proper update mechanisms in Qt. If we want to allow changing the font to begin with... (apart from a global scale)

[lmoureaux]

Related to #1292. Qt has a built-in function QApplication::setFont(const QFont &, const char *className), but it shouldn't be used together with style sheets. Another loosely related function is QStyle::polish().

[jwrober]

Not sure if it is the same issue, but if you have full screen enabled and then disable it while in game the client does not do anything. You have to get out and come back "in" (e.g. restart) to have the setting take effect.