Add code to add track to DB and remove old ones that are gone. Added fingerprint lib to link for id-ing tracks. Make sure DB is logical after these changes. Change music path due to complaints I don't quite understand.

src/db/AudioTrack.h

@@ -29,6 +29,8 @@ public:
     std::string trackArtistName;
     std::string trackAlbumName;
     std::string trackGenre;
+    double trackLengthSeconds;
+    std::string trackFingerprint;
     std::string trackPath;
     
     template<class Action>
@@ -37,6 +39,8 @@ public:
         Wt::Dbo::field(a, trackName, "name");    
         Wt::Dbo::field(a, trackArtistName, "artist");
         Wt::Dbo::field(a, trackAlbumName, "album");
+        Wt::Dbo::field(a, trackLengthSeconds, "length");
+        Wt::Dbo::field(a, trackFingerprint, "fingerprint");
         Wt::Dbo::field(a, trackGenre, "genre");
         Wt::Dbo::field(a, trackPath, "path");
     }