osxvideosink: start the loop before calling [gstview haveSuperview]
osxvideosink: start the loop before calling [gstview haveSuperview]

...as haveSuperview requires the mainloop to be running

freedesktop-unofficial-mirror/gstreamer-sdk__gst-plugins-good,freedesktop-unofficial-mirror/gstreamer-sdk__gst-plugins-good,freedesktop-unofficial-mirror/gstreamer-sdk__gst-plugins-good,freedesktop-unofficial-mirror/gstreamer-sdk__gst-plugins-good