Closes jp9000/obs-studio#940
This adds close buttons to remux dialog, output timer dialog, and advanced audio properties dialog. I also did a small refactor of the remux dialog so the buttons were consistent with other dialogs. Closes jp9000/obs-studio#876
Adds audio monitoring selection to advanced audio properties, and adds the ability to select the device in advanced settings.
This is to prevent confusion both when prefixing commits and when reading the directory structure for the first time.
