Using nullptr instead of NULL.
Renamed the MiscDialog to SettingsDialog.
Added the AboutDialog.
Trimmed down the SettingsDialog.
"Misc" is now something like a hamburger menu for multiple things.
Make the AboutDialog accessible.
Title for the AboutDialog.
Stuff.

It's getting late.
Removed a unused slot.
Comment.
I wonder what this 'w' was supposed to mean...

... Window!
Removed unused includes.
Tooltips and a shortcut.
Try to suggest a fitting filename when advanced muxing.