Rename programoutput to auxoutput and make configurable

[Kunsi]

Ideally, i'd be able to configure each and every pipeline step to play out whereever i want. Resolution and audio yes/no should be configurable per output. There should be the possibility to output a source to multiple outputs.

Sources:

• Each input source
• mix
• mix-blinded

Outputs:

• local HDMI (framebuffer playout)
• decklink output
• raspberry pi screen (maybe that's just framebuffer? don't know, let's find out)

[Kunsi]

Current Meeting says we might want to have "slides+audio" as source, and possibly NDI as output.