[vdr] eHD and how subtitle timing start work

There has been several discussion about eHD dvb subtitle timing. Vdr works correctly on this area and time subtitles as they should be. Reelbox-plugin do not deliver timing info (STC) with default settings. The catch is soundcard support. For audio delay adjustment reelbox-plugin deliver STC. So just turn "Analog audio" to "Soundcard" and STC is delivered to VDR and subtitles are in time.

Only issue after this is with replaying recording, it will took some time to get STC to correct value. For this it would be nice to get min and max value for subtitle delay. If delay is out of those limits, vdr would use middle setting.