Do NOT accept any media type when load with embedded subtitle is NOT set.
Do NOT fail when JoinFilterGraph even if ShouldWeAutoload return false
Do NOT create tray thread when JoinFilterGraph, instead do it when CompleteConnect or the first time the graph pause. And do NOT check splitter.
Minor changes.
Workaround for external subtitle with mpc-hc: when working under mpc-hc, if there's no subtitle output pin found on known splitters, XySubFilter won't expose any input pin.