Add popup when selecting a song from the file list.
Change "updateFunnelItem" to send message with ID addes the song
Update playlist popup with warning message (if user doesn't have any items added yet)
Update challenge button on playlist
Add challenger screen to select own song (and styled)
Add 'selection' object to be send to host when user chooses the opponent and own song
Update challening popup, game will start in the playlist.