Implement basics of voting ui. Change vote selection code to also inject cover before putting in list. Make sure player sends winning track to highlight on client.

src/WebInterface.h

@@ -37,7 +37,7 @@ public:
     void skipVotedFromServer(User userRequestingToSkipCurrentTrack);
     void skipVoteUpdateFromServer(User userVoting, bool forSkip);
     void voteNextSongFromServer(User userVoting, AudioTrack trackVoted);
-    void voteNextPollClosedFromServer();
+    void voteNextPollClosedFromServer(AudioTrack winner);
     User currentUser;
 private:
     struct internal;