vdr-plugin-burn

After upgrading from beta4 to beta5, the burn plugin tries to invoke vdrsync for demuxing if beta4 was configured to use projectx for it (projectx was DemuxType 1 in beta4, but it's DemuxType 0 in beta5). A fix that also removes the remnants of vdrsync support is attached. After applying the patch, buffers.c can be removed too.