Making Luxor work completely inside Javis

[Wikunia]

Is your feature request related to a problem? Please explain.
Sometimes one wants to just draw a single image inside a bigger Javis project for example inside Pluto.
Then one gets weird errors like CURRENT_VIDEO is empty.

Describe the solution you'd like
Based on my discussion with @gpucce it would be great to be able to use

@png begin 

end

as an example outside of any animation. One probably needs to just check that one calls the Luxor functions for those that are overwritten by Javis otherwise. Which means checking if the video is empty and then calling the Luxor functions.

I'll have a look how difficult this is in the next couple of days.