#115 Configurable exclusion list for key combinations to pass to OS

[Stephen Clark]

DOSBox has exclusive use of the keyboard in fullscreen mode. Maybe have an exclusion list of configurable key conbinations that DOSBox passes to the OS?
Currently, in fullscreen mode:
1. There is no way to adjust audio volume on my laptop.
2. I cannot use Alt-Tab or Windows/Super key to access desktop, etc.