[UI] Various improvments in audio view

src/metadata/AvFormat.cpp

@@ -114,6 +114,9 @@ AvFormat::parse(const boost::filesystem::path& p, Items& items)
 		// Duration
 		items.insert( std::make_pair(MetaData::Type::Duration, boost::posix_time::time_duration( boost::posix_time::seconds( input.getDurationSecs() )) ));
 
+		// Cover
+		items.insert( std::make_pair(MetaData::Type::HasCover, input.getNbPictures() > 0));
+
 		// Embedded MetaData
 		// Make sure to convert strings into UTF-8
 		std::map<std::string, std::string>::const_iterator it;

src/metadata/MetaData.hpp

@@ -39,18 +39,12 @@ namespace MetaData
 		DiscNumber,		// size_t
 		Date,			// boost::posix_time::ptime
 		OriginalDate,		// boost::posix_time::ptime
-		Cover,			// GenericData
+		HasCover,		// bool
 		AudioStreams,		// vector<AudioStream>
 		VideoStreams,		// vector<VideoStream>
 		SubtitleStreams,	// vector<SubtitleStream>
 	};
 
-	// Used by Cover
-	struct GenericData {
-		std::string mimeType;
-		std::vector<unsigned char> data;
-	};
-
 	// Used by Streams
 	struct AudioStream {
 		std::size_t nbChannels;