utils/player: execute player.resize() and player.set_scene() from the caller thread
utils/player: execute player.resize() and player.set_scene() from the caller thread

Allows Viewer.configure() to be executed from the main thread which is
now mandatory on macOS Catalina.

gopro/gopro-lib-node.gl,gopro/gopro-lib-node.gl,gopro/gopro-lib-node.gl,gopro/gopro-lib-node.gl