[vdr] VDR-1.3.44: speedup patch for cRemux::ScanVideoPacket()

Hi,

the attached patch speeds up ScanVideoPacket() in two ways:

- finding the start code is done by memchr(), which was the major change for the cVideoRepacker speedup patches some VDR versions ago.

- ScanVideoPacket() may skip scanning the packets most of the time when cVideoRepacker is enabled (see source comments for details).

As a result, the CPU load of my EPIA system with a 600 MHz CPU drops from 27 % to 17 % for receiving the 'ASTRA HD' HDTV demo channel.

Besides the mentioned improvements, I've declared ScanVideoPacket() and GetPacketLength() static and pubic, as I'd like to use their functionality in future versions of vdr-xine.

Bye.