basic support for videoX and audioX devices

Hi,

currently libdvbv5 generate warning about ignoring dvb output devices (videoX and audioX):
WARNING Ignoring device /dev/dvb/adapter0/audio0 WARNING Ignoring device /dev/dvb/adapter0/video0
and does not allow search and open those devices.

DVB output device are used (for example) in Linux based STB devices and IMHO would be nice to be able to handle them with libdvbv5.

Attached patch enabled elementary support for those devices - remove warning and allow search it by dvb_dev_seek_by_adapter(), open and close with dvb_dev_* functions.

Best Regards,
Robert Paciorek

index 6dbd2ae..2eeae51 100644
@@ -62,6 +62,8 @@ enum dvb_dev_type {
 	DVB_DEVICE_NET,
 	DVB_DEVICE_CA,
 	DVB_DEVICE_CA_SEC,
+	DVB_DEVICE_VIDEO,
+	DVB_DEVICE_AUDIO,
 };
 
 /**

index 9a0952b..c379f40 100644
@@ -37,7 +37,7 @@
 #endif
 
 const char * const dev_type_names[] = {
-        "frontend", "demux", "dvr", "net", "ca", "sec"
+        "frontend", "demux", "dvr", "net", "ca", "sec", "video", "audio"
 };
 
 const unsigned int