Feature Request: blanking the screen

[jonaslorenz]

This awesome little program would be even more awesome if one would be able to interrupt the presentation and blank the presentation screen.

A key press would turn the presentation screen black, another one would show the current slide again.
This would allow for easier use of a blackboard/whiteboard or other media during the presentation.
I would preferentially bind this function to the "b"-key (as in other widely-used presentation software) for compatibility with various presentation remotes and user habits.

I imagine this feature would not be too hard to implement, so maybe we will see something like this soon?
Thanks a lot and keep up the good work!