Apps like Shazam and SoundHound have significantly reduced the stress of hearing a songs you like and being unable to identify them — but turning those discoveries into something you can actually play back again and again isnt always a straightforward process, particularly as streaming services have caught on. SoundHound is changing that with the introduction of the Add to Spotify button to its iOS app, which lets the user automatically create a playlist on their Spotify account using songs theyve identified in SoundHound. …