graphics/pdfpc: import pdfpc-4.4.0

pdfpc is a GTK-based presentation viewer which uses Keynote-like
multi-monitor output to provide meta information to the speaker
during the presentation. It is able to show a normal presentation
window on one screen while showing a more sophisticated overview
on the other one, providing information like a picture of the next
slide, as well as the time left in the presentation. pdfpc processes
PDF documents, which can be created using nearly all modern
presentation software.

(ryoon)