Suggestions for new features (majority playlist related)

Hi! I have been using doubleTwist for.. I think, at least 7 or 8 years now? Using it nearly every day, for hours on end. 

I make a lot of playlist and sort through my music library using the Cloud Player and I would like to suggest a few things that would be great additional features.

• Being able to move songs from one playlist to another. Right now I select them, add to the playlist of choice, and then have to select them again to remove them from the original playlist.
• Being able to add songs to multiple playlists at once. Like a multiple choice menu instead of the current single-click one.
• Ability to search for doubles/remove doubles in a playlist. 
• A feature that enables you to sort playlists into groups. I have a lot of playlists, and both the list view thumbnail view is still a bother to scroll down. Would love to be able to sort playlists into minor folders. 
• Being able to locate your currently playing song in a playlist (maybe by a simple button somewhere?) Say you want to start the random shuffle with a specific song - to do this currently, you would have to search for the song, click on it (which shuffles only the search results), then go back til you see the blue icon indicating it's playing, and click the song again from the full list. Kind of complicated.
• Being able to choose a thumbnail to represent the playlist. :) Just a minor thing. 
• As for UI, I remember one time a long while ago when you could enter a playlist, play a song, browse the album or artist (add more songs from them to your playlist, maybe), and clicking the back button would take you directly back to the playlist you were in. After an update a few years ago this changed, so when you click back you're instead taken to the album library. Which just means a few extra clicks to go back to the playlist you were editing, but it gets tiring after a while.
• I would also suggest moving the "added to ___ playlist" notification that shows up in the middle of the screen. It's very minor, but sometimes when you're doing things quick and just want to spam a song into multiple playlists (because selecting multiple isn't possible), it gets in the way of the buttons. The notification itself is nice because it lets you know it worked, maybe just move it up or down, or into a corner?
• And it would be very nice if you could click and drag to select songs in a playlist! Instead of having to click them all separately. Sometimes I just want to remove the lowest rated bunch when I'm done listening to them and it would be nice to be able to do it in a simple sweep. 

Thank you so much for an amazing app! And thanks if someone took the time to read through these suggestions. :)