Revert "Copy Arcade and NDS plugins into the app"

This reverts commit 0ed12fe357d248005b1208e906b9cb190b1bf703.
Adds preliminary support for audio output device selection per issue #546. The cog menu in the HUD controls bar now contains a Select Audio Output Device submenu. There’s still no preference and the menu doesn’t show the audio device that’s being used for output, but it should be functional.
Code cleanup.
Merge remote-tracking branch 'upstream/master'